Glossary of botanical terms | Wikipedia audio article

This glossary of botanical terms is a list
of terms relevant to botany and plants in general. Terms of plant morphology are included
here as well as at the related Glossary of plant morphology and Glossary of leaf morphology.
See also List of Latin and Greek words commonly used in systematic names. You can help by
adding illustrations that assist an understanding of the terms.==A==
ab- A prefix meaning “from, away from, or outside”. abaxial
The surface of an organ facing away from the organ’s axis, e.g. the lower surface of a
lateral organ such as a leaf or petal. abort
To abandon development of a structure or organ. abscission
The shedding of an organ that is mature or aged, e.g. a ripe fruit or an old leaf. abscission zone
A specialised layer of tissue that allows an organ to be shed by abscission when it
is ripe or senescent. Commonly formed, for example, at the base of a petiole or pedicel. acaulescent
Having no apparent stem, or at least none visible above the ground surface. Examples
include some species of Agave, Oxalis and Attalea. accrescent
Increasing in size with age, such as a calyx that continues to grow after the corolla has
fallen, for example in Physalis peruviana. -aceae
A suffix added to the stem of a generic name to form the name of a taxonomic family; for
example, Rosaceae is the rose family. achene
A dry, 1-seeded indehiscent fruit, e.g. in the genus Ranunculus. acicular
Slender or needle-shaped. acropetal
Moving from roots to leaves, e.g. of molecular signals in plants. acrophyll
The regular leaves of a mature plant, produced above the base; usually used in contrast to
bathyphyll. acrostichoid
(describing a type of sorus) Covering the entire abaxial surface of a frond, usually
densely so, as in Elaphoglossum and Acrostichum. actino-
A prefix that indicates a radial pattern, form, or morphology. actinodromous
(leaf venation) Palmate or radially arranged venation with three or more primary veins
arising at or near the base of the leaf and either reaching the margin or not. actinomorphic
Regular; radially symmetrical; may be bisected into similar halves in at least two planes.
Applies e.g. to steles and flowers in which the perianth segments within each whorl are
alike in size and shape. Compare regular; contrast with asymmetrical, irregular, and
zygomorphic. aculeate
Armed with prickles, e.g. the stem of a rose. acuminate
Tapering gradually to a point. acute
Sharply pointed; converging edges making an angle of less than 90°. Compare obtuse. ad-
A prefix meaning “near or towards”; also meaning “added to”. adaxial
The surface of an organ facing towards the organ’s axis, e.g. the upper surface of a
lateral organ such as a leaf or petal. adnate
Grown or fused to an organ of a different kind, especially along a margin, e.g. a stamen
fused to a petal. Compare connate. adventitious
A structure produced in an abnormal position, e.g. an adventitious bud produced from a stem
rather than from the axil of a leaf. adventive
Introduced accidentally (usually referring to a weed). aerial
Of the air; growing or borne above the surface of the ground. aestivation
The arrangement of sepals and petals or their lobes in an unexpanded flower bud. Compare
vernation, the arrangement of leaves in a bud. aff. (affinis)
With affinity to others, akin to; often used for a provisionally recognized but unnamed
taxon considered close to that name, perhaps a hybrid or extreme variant. aggregate fruit
A cluster of fruits formed from the free carpels of one flower, e.g. a blackberry. Compare
multiple fruit. agricultural weed
See weed. alate
Having a wing or wings. albumen
An older name for the endosperm of flowering plants. Except for being a storage tissue
for nutrients, it is not at all like the albumen (egg white) of animal embryos. albuminous
(seeds) Containing endosperm. -ales
A suffix added to the stem of a generic name or descriptive name to form the name of a
taxonomic order. alien
A plant introduced to an area outside its natural range. Often synonymous to or used
in combination with foreign, exotic, non-native, and non-indigenous. alkaloid
A molecule with a nitrogenous base, often used as a drug, e.g. morphine, quinine, and
strychnine, each of which occurs naturally in certain plants. alternate
1. (adj.) Leaves or flowers borne singly at different levels along a stem, including spiralled
parts. 2. (prep.) When something occurs between something
else, e.g. stamens alternating with petals. Compare opposite. ament
A synonym of catkin. amphitropous
When the ovule is bent so that both ends are near each other. Compare anatropous, campylotropous,
and orthotropous. amplexicaul
With the base dilated and clasping the stem, usually of leaves. anastomose
Branching and then rejoining, as with leaf venation. anastomosis
A connection or fusion of two or more veins that are normally diverging or branching,
thereby forming a network. anatropous
When an ovule is inverted so that the micropyle faces the placenta (this is the most common
ovule orientation in flowering plants). Compare amphitropous, campylotropous, orthotropous. androdioecious
Of plants, having bisexual flowers and male flowers on separate individuals. Compare andromonoecious,
polygamodioecious, polygamomonoecious, polygamous. androecium
Male parts of flower; the stamens of a flower collectively. Compare gynoecium. Abbreviation:
A. For instance A 3+3 indicates 6 stamens in two whorls. androgynophore
A stalk bearing both the androecium and gynoecium of a flower above the level of insertion of
the perianth. androgynous
With male and female flowers in the same inflorescence. androphore
The stalk or column supporting the stamens in certain flowers. andromonoecious
Having bisexual flowers and male flowers on the same individual plant. Compare gynomonoecious,
polygamodioecious, polygamomonoecious, and polygamous. anemophily
Pollination by wind. angiosperm
A flowering plant; a plant with developing seeds enclosed in an ovary. anisomery
The condition of having a floral whorl with a different (usually smaller) number of parts
from the other floral whorls. anisotomic
branching with branches having unequal diameters, such as a trunk and its branch, compare to
isotomic. annual
A plant that completes its life cycle (germinates, reproduces and dies) within one year. annulus
Ringlike; in the form of a ring. Pappus bristles are sometimes attached to a ring (annulus
or disk) at the top of the achene beak. In some pollen grains, the exine around the apertures
is either thicker or thinner. In pores this border is termed annulus. Having a ring-like
constriction (annulus) at the mouth of the flower as in Huernia or Aristolochia. A ring
of specialized cells on the sporangium. anthemoid
In Compositae, style with a brush-like tuft of sweeping hairs at the tip of each style
branch. anthocarp
A type of fruit in which some part of the flower persists, attached to the pericarp,
as in Nyctaginaceae. anterior
Positioned in front of, towards the apex. Compare distal. anther
Pollen-bearing part of the stamen. antherode
A sterile anther of a staminode. anthesis
1. (of a flower) The period during which pollen is presented and/or the stigma is receptive.
2. (of a flowering plant) The period during which flowers in anthesis are present. Not
defined for some cases, such as when pollen is released in the bud. anthophore
A stalk-like structure, internode located between the calyx and the other parts of the
flower. anticlinal
Pointing up, away from or perpendicular to a surface. Compare periclinal. antrorse
Directed towards or upwards, e.g. of hairs on a stem. Compare retrorse. apetalous
Lacking petals. apex
pl. apices The tip; the point furthest from the point of attachment.
aphananthous (of flowers) Inconspicuous (unshowy), as opposed
to phaneranthous (showy). aphlebia
pl. aphlebiae Imperfect or irregular leaf endings commonly found on ferns and fossils
of ferns from the Carboniferous Period. apiculate
(usually referring to a leaf) Terminating in a short, sharp, flexible point; less abrupt
than mucronate. apiphily
A form of pollination whereby pollen is distributed by honey bees. apo-
A prefix meaning “away from, separate, without”. apocarpous
(of a gynoecium) Consisting of one or more carpels which are free from one another (or
almost so), e.g. in members of the Ranunculaceae and Dilleniaceae. apomixis
A type of reproduction whereby viable seeds or spores are produced without fertilization.
A plant produced in this way is called an apomict. apomorphy
In cladistics, a “different form” from the form of an ancestor (i.e., an innovation)
of use in determining membership in a clade. apophysis
The external part of a cone scale; an outgrowth of an organ or enlargement of a stem. appendage
A secondary part attached to the main structure; an external growth that seldom has any obvious
function, hence appendiculate. appendiculate
Having the nature of or bearing appendage(s). appressed
Pressed closely but not fused, e.g. leaves against a stem. aquatic plant
A plant whose natural habitat is water, living in or on water for all or a substantial part
of its lifespan; generally restricted to fresh or inland waters. arachnoid
Cobwebby, from being covered with fine white hairs. arborescent
Tree-like in growth or general appearance. arboretum
pl. arboreta A taxonomically arranged collection of trees.
archaeophyte A non-native plant that has been present in
a geographic area for some time. Compare neophyte. arctotoid
In Compositae, style with a ring of sweeping hairs borne on the shaft of the style proximal
to the style branches. areolate
Having or being composed of areoles, as an areolate crustose lichen. areole
A space between the threads of a net, e.g. that part of a leaf surface defined by each
of the elements of a vein network; as with cacti, the area between the veinlets of a
leaf or the region of a cactus where spines and flowers are borne. In lichenology, an
areole is a polygonal piece of a thallus surface when a crustose lichen it broken up like old
dried and cracked paint, or like the polygonal “islands” of dried mud in a dry lake bed. aril
A membranous or fleshy appendage (formed by expansion of the funicle) which partly or
wholly covers a seed, e.g. the fleshy outer layer of lychee fruit, or that found in members
of the Sapindaceae. aristate
With a stiff, bristle-like awn or tip. article
A segment of a jointed stem or of a fruit with constrictions between the seeds; an organ
part that separates easily from the rest of the organ at a joint or articulation. articulate
Jointed; separating freely, leaving a clean scar; for example, the fronds of certain ferns
where they join the rhizome. ascending
Spreading horizontally, then becoming erect. ascocarp
The fruiting body (sporocarp) of an ascomycete fungus. ascomycete
A member of the Ascomycota. Ascomycota
A division (botany) or phylum of fungi commonly called sac fungi. It is separated from the
division Basidiomycota asexual reproduction
Reproduction that does not involve gametes. Often used synonymously with vegetative reproduction. asymmetrical
Irregular, unequal; lacking any plane of symmetry. attenuate
Narrowing gradually. auricle
An ear-shaped lobe. awn
Long, bristle-like appendage, e.g. terminating or on the back of glumes and/or lemmas of
some grass spikelets, and the so called awn in the Geraniaceae is the (part of the) style
that remains attached to the carpel that separates from the carpophore (column). A generally
straight, stiff pappus element, varying from stiffly bristle-like to hard and needle-like.
In Strophanthus the awn is the beak of the seed, stipe of the coma hairs. axil
The upper angle between one part of a plant and another, e.g. the stem and a leaf. axile
On an axis; of a placenta, on the central axis of the ovary. axillary
Borne in or arising from the axil of a leaf. axis
The main stem of a whole plant or inflorescence.==B==
baculiform Rod-like; longer than wide. Compare cylindrical. barb
A rear-facing point, as in a fish hook. barbed
Having barbs pointing in one direction. barbellate
Having barbed hairs (barbellae). bark
The protective external layer of tissue on the stems and roots of woody trees and shrubs;
includes all of the living and non-living tissue external to the cambium. basal
Situated or attached at the base. basifixed
Something attached by its base, e.g. an anther attached to the filament. Compare dorsifixed. basipetal
developing sequentially from the apex towards the base (i.e. with the youngest towards the
base), e.g. of flowers in an inflorescence. Also, moving from leaves to roots, e.g. of
molecular signals in plants. bathyphyll
A specialized leaf produced at the base of a plant, usually when the plant is immature,
and which serves to anchor the plant to a substrate; especially notable in the fern
Teratophyllum. Compare acrophyll. beak
A prominent pointed terminal projection, especially of a carpel or fruit. berry
An indehiscent fruit with the seeds immersed in the pulp, e.g. a tomato. bi-
A prefix meaning “two”; for example, bisulcate, having two sulci or grooves. biennial
A plant which completes its life cycle (germinates, reproduces and dies) within two years; usually
also forms a basal rosette of leaves the first year and flowers and fruits the second year. bifid
Forked; cut in two for about half its length. Compare trifid. bifoliate
Having two leaflets (a type of compound leaf). bifusiform
Fusiform with a pinch in the middle. bilabiate
Having two lips, e.g. the form of the petals in many irregular flowers. bilateral
Arranged on opposite sides, e.g. leaves on a stem. biloculate
Having two loculi, e.g. in the anthers. binomial
Making use of names consisting of two words to form the scientific name (or combination)
in a Latin form. For example, where the first is the name of the genus to which the species
belongs, and the second is the epithet given to that species to distinguish it from others
in the same genus. binomial nomenclature
The system of nomenclature in which the scientific name of a species (and not of a taxon at any
other rank) is a combination of two names, the first name being the generic name. The
second name is referred to botanically as the specific epithet. Note that the two names
constitute the species name, not just the second word. bipinnate
Doubly pinnate; for example, of a compound leaf with individual leaflets pinnately divided. bipinnatisect
A pinnatisect leaf with deeply dissected segments. bisexual
Bearing both male and female reproductive organs; usually, flowers with both stamens
and carpels; synonymous with hermaphrodite, synoecious, and monoclinous. Bisexual flowers
only occur on monoecious plants. See also androgynous, monoicous, and plant reproductive
morphology. bitegmic
(of an ovule) Covered by two integuments. biternate
Ternate, with each division divided into three. bivalve
Having two valves or hinged parts. See also trivalve. blade
The lamina or flattened part of a leaf, excluding the stalk. bloom
A fine white or bluish waxy powder occurring on plant parts, usually stems, leaves and
fruits. It is easily removed by rubbing. bole
The trunk of a tree, usually the portion below the lowest branch. Compare canopy. bostrychoid
arranged on a conical surface (like a snail shell): used to describe inflorescences where
the buds are arranged in an almost helical manner on the outside of a long tapering conical
rachis. bract
A modified leaf associated with a flower or inflorescence and differing in shape, size
or colour from other leaves (and without an axillary bud). bracteate
Possessing bracts. bracteole
A small bract borne singly or in pairs on the pedicel or calyx. Also called a bractlet. bracteolate
Possessing bracteoles (bractlets). bractlet
See bracteole. branchlet
A small branch. brevideciduous
A plant that loses all of its leaves briefly, so that it is leafless for only a short time,
e.g. approximately two weeks. bristle
A straight, stiff hair (smooth or with minute teeth); the upper part of an awn (when the
latter is bent and has a lower, stouter, and usually twisted part, called the column). brochidodromous
Pinnate leaf venation in which the secondary veins do not terminate at the leaf margin,
but are joined in a succession of prominent arcs. bryophyte
Informally, a collective term for the mosses, hornworts and liverworts. Formally, these
plants are placed in three separate divisions: hornworts (Anthocerophyta), liverworts (Marchantiophyta)
and mosses (Bryophyta). bulb
A thick storage organ, usually underground, consisting of a stem and leaf bases (the inner
ones fleshy). bulbel
A bulb arising from another bulb. See bulblet. bulbil
A small, deciduous bulb or tuber formed in the axil of a leaf or pinna; a means of vegetative
propagation. bulblet
A bulb arising from another bulb; a bulbil. bullate
Having rounded or globular blisters on the surface. burr
A prickly fruit; a rough or prickly propagule consisting of a seed or fruit and associated
floral parts or bracts. buttress root
A root growing from an above-ground stem or trunk, and providing support, as in the case
of Ficus macrophylla. byssoid
A growth form of a lichen thallus that is whispy, like teased wool.==C==
C, C−, C+ In lichenology, “C” is an abbreviation for
the test result of placing 5% solution of calcium hypochlorite or sodium hypochlorite
(e.g. household bleach without additives) on the cortex or the medulla of a lichen,
to note the change in color, with no reaction noted as “C−”, and production of a bright
colour noted as “C+”. caducous
Falling off early; for example, the sepals of poppies, which fall off when the petals
begin to open. Compare persistent and fugacious. caespitose
Tufted, e.g. the growth form of some grasses. calcareous
A soil type that is rich in calcium carbonate; a lichen substrate rock type that is largely
composed of calcium carbonate. callose
Hardened, thickened, callous. callus
1. pl. calli A protruding mass of tissue. 2. Undifferentiated tissue growth formed in
response to wounding; may be grown in vitro. 3. In orchids, fleshy outgrowths from the
labellum which can be variously shaped from papillae to plates.
4. In grasses, a hardened extension from the base of a floret (formed from the rachilla
joint and/or the base of the lemma) which may or may not elongate and is often covered
in hairs or bristles. calyciflorous
Having petals and stamens attached to the calyx. calycophyll
A leaf-like structure formed from a sepal or calyx lobe which enlarges, usually many-fold,
before or after anthesis, especially when most of the sepals or calyx lobes retain their
original size. More extreme than an accrescent calyx, calycophylls are found in Rubiaceae.
cf. semaphyll, pterophyll. calyculate
Having an epicalyx. calyculus
1. A cup-shaped structure formed from bracts. 2. In some Asteraceae, a circle of bracts
below the involucre. calyptra
A hood or lid. See operculum. calyx
pl. calyces A collective term for the sepals of one flower; the outer whorl of a flower,
usually green. Compare corolla. calyx tube
A tube formed by the fusion of the sepals (calyx), at least at the base. cambium
A tissue layer that provides partially undifferentiated cells for plant growth. coma
Tuft of hairs from testa or funiculus at one or both ends on some seeds, as in Strophanthus,
Asclepias or Alstonia, or sterile bracts, as in Curcuma, Ananas or Eucomis, or sterile
flowers as in Muscari, Leopoldia, at the apex of some plant inflorecences. A tuft of hairs
at the base of some flowers as in Pfaffia gnaphalioides, a tuft of hairs at the apex
or base on some spikelets. An axil tuft of hairs in inflorescences in some Poaceae as
in Eragrostis comata. campanulate
Bell-shaped. camptodromous
Pinnate venation in which the secondary veins curve toward the margins, in some cases becoming
nearly parallel with them, and not reconnecting with other veins to form loops. campylotropous
When the ovule is oriented transversely (i.e. with its axis at right angles to its stalk)
and with a curved embyro sac. Compare amphitropous, anatropous, orthotropous. canaliculate
Channelled; having a longitudinal groove. canescent
Approaching white in color, as in a leaf covered with white down or wool. canopy
The branches and foliage of a tree; the crown. Also refers to the protective upper layer
of a forest. Compare trunk. capillary
1. (n.) A tube, pore or passage with a narrow internal cross-section.
2. (adj.) Slender, hair-like. capitate
Having a knob-like head; of an inflorescence, with the flowers unstalked and aggregated
into a dense cluster; of a stigma, like the head of a pin. capitulum
A dense cluster of sessile, or almost sessile, flowers or florets, e.g. a flower head in
the daisy family Asteraceae. see pseudanthium and pseudanthium. capsule
A dry fruit formed from two of more united carpels and dehiscing when ripe (usually by
splitting into pieces or opening at summit by teeth or pores). carduoid
In Compositae, style with a ring of sweeping hairs borne on the shaft of the style below
the style branches. carina
See keel. carinal canal
A longitudinal cavity in the stems of Equisetum and extinct Equisetopsida, coinciding with
a ridge in the stem surface. carpel
The basic female reproductive organ in angiosperms, either consisting of a single sporophyll or
a single locule of a compound ovary, with a style and a stigma. The gynoecium is the
collective term for all of the carpels of a single flower. carpopodium
On Achenes (Cypselas) an elongation of the base of the gynoecium which looks distinct.
The abscission zone, where the achene is separated from the receptacle. cartilaginous
Hard and tough; gristly. caryopsis
A dry, indehiscent, one-seeded fruit in which the seed coat is closely fused to the fruit
wall, as in most grasses. Casparian strip
A continuous band of suberin in the radial primary cell walls of the endodermis in vascular
plant stems and roots that forms a permeability barrier to the passive diffusion of external
water and solutes into the vascular tissue. casual alien
A plant that appears with no apparent human assistance but does not develop a sustained
population(s). Plants that persist only by new introductions. Compare alien. cataphyll
Early leaf forms of plants or shoots, such as cotyledons, bud-scales, rhizome-scales;
anatomically they are leaves, but do not develop to perform the usual functions of photosynthetic
leaves. catkin
A spike, usually pendulous, in which the mostly small flowers are unisexual and without a
conspicuous perianth, e.g. willows, poplars, oaks and casuarinas. The individual flowers
often have scaly bracts; they are generally wind-pollinated. The catkins are usually shed
as a unit. caudate
Having a narrow tail-like appendage or tip, e.g. a drip tip. Compare acuminate. caudex
pl. caudices The stem of a plant; also used to mean a rootstock, or particularly a basal
stem structure or storage organ from which new growth arises.
caudiciform Stem-like or caudex-like; sometimes used to
mean “pachycaul”, meaning “thick-stemmed”. cauline
Borne on an aerial stem (caulis), e.g. leaves, flower or fruits (when applied to the latter
two organs, usually referring to older stems;=cauliflorous). cell
1. The basic, microscopic unit of plant structure, generally consisting of compartments in a
viscous fluid surrounded by a cell wall. 2. A cavity of an anther or ovary. centrifixed
Of a two-branched organ attached by its centre, e.g. a hair or anther. cespitose
An alternative spelling of caespitose. chartaceous
Having a papery texture. chamber
A cavity of an ovary. channelled
Sunken below the surface, resulting in a rounded channel. chasmogamous
Of flowers that are pollinated when the perianth is open. Compare cleistogamous. chasmophyte
A plant adapted to growing in crevices or hollows, such as in cliff faces. Compare cremnophyte. chimera
An individual composed of two or more genetically different tissues, most commonly as a result
of a graft and sometimes within the individual, by mutations and irregularities that occur
during cell division. chiropterophilous
Pollinated by bats. chlorophyll
A green pigment in chloroplasts essential for photosynthesis. chloroplast
An organelle present in plant cells which contains chlorophyll. chlorosis
An abnormal lack or paleness of color in a normally green organ. cilia
sing. cilium; adj. ciliate Very small hairs or hair-like protrusions more or less confined
to the margins of an organ, as with eyelashes; in motile cells, minute, hair-like protrusions
which aid motility. circinate
Spirally coiled with the tip innermost, e.g. circinate vernation of the developing fronds
of most ferns. cladode
A photosynthetic stem, often leaf-like and usually with foliage leaves either absent
or much reduced. Compare phyllode. class
The principal category for taxa ranking between division and order. clathrate
Shaped like a net or lattice; pierced with apertures, as with a cage. clavate
Club-shaped. claw
1. A narrow, stalk-like, basal portion of a petal, sepal or bract.
2. In Melaleuca, the united portion of a stamen bundle. cleistogamous
Having flowers which self-pollinate and never open fully or self-pollinate before opening.
Compare chasmogamous. climber
A plant growing more or less erect by leaning on or twining around another structure for
support, or by clinging with tendrils. cline
adj. clinal A continuous morphological variation in form within a species or sometimes between
two species. clone
A plant derived from the vegetative reproduction of a parent plant, with both plants having
identical genetic constitutions. coalescent
Having plant parts fused or grown together to form a single unit. cochleariform
Concave and spoon-shaped. cochleate
Coiled like a snail’s shell. coenobium
An arranged colony of algae that acts like a single organism. coenocyte
A single cell with multiple nuclei, formed when nuclear division was not followed by
cytokinesis. collenchyma
A specialized tissue consisting of living cells with unevenly thickened cellulose and
pectin cell walls that performs a support function in organs such as leaves and young
stems that are composed of primary plant tissues. colleter
A multicellular, glandular hair that usually produces a mucilaginous substance and is located
on sepals, stipules, or petioles, or on nearby parts of stems; commonly found on plants in
the order Gentianales. columella
In flowering plants, the central axis of the cone or fruit, e.g. in Callitris. column
1. A structure extending above ovary and incorporating the style and stamens; gynostemium, e.g. in
orchids. 2. In grasses, the lower, stouter, and usually
twisted part of an awn, distinct from the slender upper part or bristle. columnar
Shaped like a column. commercial name
A name often of no botanical standing and not governed by the ICNCP. The term generally
applies to names such as Trademark Names, names covered by Plant Breeders Rights, Patents
and Promotional Names, which are often used to enhance the sale of a plant. commissure
The seam or face at which two carpels adhere. community
An ecological assemblage of plants that characteristically occur together. compound
Composed of several parts, e.g. a leaf with leaflets, a gynoecium with several carpels,
or an inflorescence made up of smaller inflorescences. compound palmate
Having leaflets that radiate from a central point (usually at the top of a petiole) like
spread-out fingers radiating from the palm of a hand. compressed
Flattened lengthwise, either laterally (from side to side) or dorsally (from front to back). concolorous
Having the same colour throughout; uniformly coloured. conduplicate
Arranged such that two sides of a flat surface are folded along the midline to face each
other. See also ptyxis, aestivation, and vernation. cone
A fruit, usually woody, ovoid to globular, including scales, bracts or bracteoles arranged
around a central axis, e.g. in gymnosperms, especially conifers and Casuarina. conflorescence
A rarely used term describing substantial differences between the overall structure
of an inflorescence and that of its individual branches, e.g. the bottlebrush multiple-flower
head of members of the genus Callistemon. connate
Fused to another organ (or organs) of the same kind, e.g. petals in a corolla tube.
Compare adnate. connective
The part of an anther that connects the anther cells. connivent
Coming into contact or converging. conspecific
Belonging to the same species. contiguous
Adjoining, touching, but not united. contort
(of sepals and petals) A type of imbricate aestivation in which one side of each segment
overlaps one of the adjacent segments and the other side is overlapped by the other
adjacent segment. See convolute. contorted
Twisted out of the normal shape. convolute
1. Referring to the arrangement of floral or foliar organs in a bud when each organ
or segment has one edge overlapping the adjacent organ or segment; a form of imbricate arrangement;
contort. 2. (of leaves) A type of vernation in which
one leaf is rolled up inside another. 3. A type of vernation of two leaves at a
node, in which one half of each leaf is exposed and the other half is wrapped inside the other
leaf. cordate
Heart-shaped, with the notch lowermost; of the base of a leaf, like the notched part
of a heart. coriaceous
Leathery; stiff and tough, but somewhat flexible. corm
A fleshy, swollen stem base, usually underground and functioning in the storage of food reserves,
with buds naked or covered by very thin scales; a type of rootstock. Adjectives derived from
“corm” include “cormose” and “cormous”. corolla
A collective term for the petals of a flower. Compare calyx. corona
1. In flowering plants, a ring of structures that may be united in a tube, arising from
the corolla or perianth of a flower and standing between the perianth lobes and the stamens.
The trumpet of a daffodil is a corona. 2. In grasses, a hardened ring of tissue surmounting
the lemma in some species. cortex
pl. cortexes, cortices In lichens, the “skin” or outer layer of thallus tissue that covers
the medulla. Fruticose lichens have one cortex encircling the branches, even flattened, leaf-like
forms; foliose lichens have different upper and lower cortices; crustose, placodioid and
squamulose lichens have an upper cortex but no lower cortex; and leprose lichens lack
any cortex. corticolous
Growing on bark or on wood with the bark stripped off. Compare lignicolous. corymb
adj. corymbose An inflorescence with branches arising at different points but reaching about
the same height, giving the flower cluster a flat-topped appearance.
costa A rib. costapalmate
Having a definite costa (midrib), unlike the typical palmate or fan leaf, but with the
leaflets arranged radially as in a palmate leaf. cotyledon
The primary leaf or leaves of a plant embryo which upon germination develops into the seed-leaf
or the first set of leaves. craspedodromous
Pinnate venation in which the secondary veins terminate at the margins, often as teeth. crateriform
In the shape of a saucer or shallow cup; hemispherical or more shallow . cremnophyte
A plant adapted to growing on, especially hanging from, cliff faces or crevices. Compare
chasmophyte. crenate
Having blunt or rounded teeth; scalloped. crenulate
Minutely scalloped. crisped
Finely curled, as with the edges of leaves and petals. cristarque cell
A sclereid which contains a druse and has the lignin deposited excentrically on the
cell wall to form a cup shape, or in cross section, a ∪-shape. crown
See canopy. cross
To make something interbreed; the act of hybridization. cruciform
Cross-shaped. crustaceous
Hard, thin and brittle. crustose
Forming a closely applied surface layer or crust. cryptogams
A collective term for the “lower plants” which produce spores and do not have stamens, ovaries
or seeds; literally plants whose sexual reproductive organs are not conspicuous. Typically includes
the ferns, bryophytes and algae, and sometimes fungi (including lichenized fungi). Compare
phanerogam. cucullate
Hood-like or hooded, commonly referring to the shape of leaves or petals, e.g. Pelargonium
cucullatum. Similarly derived terms include cuculliform and cuccularis. culm
In grasses, sedges, rushes, and some other monocotyledons, an aerial stem bearing the
inflorescence; strictly, from the base of the plant to the lowest involucral bract (or
base of the inflorescence). cultigen
A plant whose origin or selection is primarily due to intentional human activity. cultivar
A term derived from “cultivated variety” denoting an assemblage of cultivated plants clearly
distinguished by one or more characters (morphological, physiological, cytological, chemical or other);
when reproduced (sexually or asexually), the assemblage retains its distinguishing characters.
A cultivar may arise in cultivation or be introduced from the wild. It is a variant
that is of horticultural interest or value. Cultivar names are written with single quotation
marks around them e.g. ‘Blue Carpet’ or ‘Alba’. All new names established after 1 January
1959 must be in common language (that is, not in Latin) but names established in Latin
prior to this date are retained in Latin form. cultivar epithet
The defining part of a name that denominates a cultivar. Cultivars are designated by fancy
(q.v.) epithets appended either to the scientific name or to the common name of the taxon to
which they belong; they are not italicized but placed in single quotation marks, for
example Rubus nitidoides ‘Merton Early’. ‘Merton Early’ is the cultivar epithet. cuneate
Wedge-shaped, with straight sides converging at base. cupule
A cup-shaped structure composed of coalescent bracts, such as the cup of an acorn. See calybium. cupular
Shaped like a cupule. cupulate
Bearing cupules. cupuliform
Nearly hemispherical, shaped like a cupola or dome. cusp
A pointed tip, hence cuspidate. cuspidate
Tipped with a cusp, as with some leaves. cuticle
A waterproofing layer covering the epidermis of aerial plant surfaces and composed of the
polymers cutin, and/or cutan and waxes. cutting
An apical tip of shoot structure, root or leaf which is cut from a plant and used for
vegetative propagation. cyathium
pl. cyathia An inflorescence of unisexual flowers surrounded by involucral bracts, especially
the flowers of Euphorbia. cyathophyll
The bract-like structure of a Euphorbia on which the involucre sits, usually but not
always occurring in twos. They may sometimes be brightly colored and confused with petals. cylindrical
Rod-like and two to three times as long as wide. Compare baculiform. cynaroid
See carduoid cyme
adj. cymose A type of inflorescence in which the main axis and all lateral branches end
in a flower (each lateral may be repeatedly branched).
cypsela A dry, one-seeded, indehiscent fruit formed
from an inferior ovary.==D==
deciduous Dehiscing and falling seasonally, as with
bark, leaves, or petals. Compare persistent. declinate
Curving downwards, and then upwards at the tip. Often qualified, e.g. declinate-ascendant. decompound
Divided to more than one level, e.g. in bipinnate leaves, in which the leaflets of what otherwise
would be a pinnate leaf are themselves pinnately divided. decorticate
To shed or peel off the outer bark of a tree. decumbent
Having branches growing horizontally along the ground but which are turned up at the
ends. decurrent
Extending downwards beyond the point of insertion, e.g. when the base of a leaf or a fungal gill
is prolonged downwards along the stem in a raised line or narrow wing. decussant
A synonym for decussate; the usage decussant is questionable and occurs rarely, probably
as an error. The formally correct usage is decussate. decusssate
Opposite with successive pairs borne at right angles to the last; generally applied to the
arrangement of leaves. definite
Of a constant number, e.g. twice as many stamens as the petals or sepals (or less), or an inflorescence
ending in a flower or an aborted floral bud, typically a cymose inflorescence. Compare
indefinite. deflexed
Bent downwards. Compare inflexed. dehiscent
Breaking open at maturity to release contents; refers e.g. to the opening of fruits to release
seeds, of anthers to release pollen and of sporangia to release spores. Compare indehiscent. deltoid
Shaped like the uppercase Greek letter Δ, i.e. like a more or less equilateral triangle. dendroid
Tree-like; branching like a tree. dentate
Toothed, especially in reference to leaf margins. denticulate
Finely toothed; a diminutive form of dentate. deserticolous
Inhabiting a desert. determinate
Limited, usually in growth. Compare indeterminate. diaspore
A reproductive part of a plant, adapted for dispersal and for establishing new plants;
a disseminule such as a seed, or specialised buds, branches, inflorescences or fruits. dichasium
A cymose inflorescence with all branches below the terminal flower in regular opposite pairs.
Compare monochasium. dichlamydeous
perianth is divided into separate calyx and corolla. Compare to homochlamydeous, in which
they are indistinguishable dichotomous
forking into two equal branches. This may result from an equal division of the growing
tip, or may be sympodial, in which the growing tip is aborted and replaced. Typically refers
to mode of branch growth, as in Aloidendron dichotomum, but also to other organs, such
as the thorns of various species of Carissa (which morphologically are branches) and thalli
or hyphae of various algae and fungi. dicotyledon
a flowering plant whose embryo has two (rarely more) cotyledons (seed leaves) (common usage:
dicot.) compare monocotyledon (common usage: monocot.). digitate
with segments spreading from a common centre, like the fingers of a hand; see also palmate,
palmatisect. dimorphic
occurring in 2 different forms (in respect to shape and/or size), for example of stamens,
fronds, leaves. See also monomorphic (having a single form) and polymorphic (many forms) dioecious
of vascular plants, when male and female reproductive structures develop on different individuals.
cf. monoecious. dioicous
of bryophyte gametophytes, when male and female reproductive structures develop on different
individuals. cf. monoicous. diploid
with two full sets of chromosomes in the nucleus of a sporophyte cell, that is one set from
each of the parental gametes. This is expressed symbolically as 2n, where n=the number of
chromosomes in the haploid gametes. diplostemonous
stamens arranged in two whorls, with the outer whorl alternating with the petals, while the
inner whorl is opposite the petals. Compare obdiplostemonous. disk (disc)
a plate or ring of structures derived from the receptacle, and occurring between whorls
of floral parts. In some groups, especially Sapindales, the nectary is in the form of
a prominent disk. In daisies, the central part of the capitulum is a disk, hence flowers
borne there are called disk flowers or florets. discoid
resembling a disc or plate, having both thickness and parallel faces and with a rounded margin.
Also used to describe the flower head of Asteraceae where there are no ray florets, but only disc
florets. discolorous
Of leaves, with upper and lower surfaces of a different colour. disjunct
Occurring in widely separated geographic areas, distinctly separate; applies to a discontinuous
range in which one or more populations are separated from other potentially interbreeding
populations far enough as to preclude gene flow between them. dissected
Deeply divided; cut into many segments. distal
Remote from the point of origin or attachment; the free end. Compare proximal. distichous
Arranged in two opposite rows (and hence in the same plane). distinct
Separate or free; not united. distyly
The condition in which the flowers of a species occur in two forms that differ only by the
length of the style and stamens, and flowers of only one of these forms appear on any one
plant. see:heterostyly diurnal
Of the day; occurring or opening in the daytime. divaricate
Wide-spreading. divergent
Spreading in different directions, generally upward. division
A taxonomic rank below kingdom in the standard taxonomic hierarchy; the approximate botanical
equivalent of phylum, which is used for animals and other kingdoms. domatia
(sing. domatium) Any hollow structure formed by a plant that is inhabited by animals such
as ants or mites. dorsal
At the rear or back, facing away from the axis (abaxial) in a lateral organ or away
from the substrate in a prostrate plant. dorsifixed
Attached at or by the back, e.g. anthers on a filament. dorsiventral
Having structurally different upper and lower surfaces, e.g. some leaves. drip tip
A long, narrow, caudate or acuminate extension at the tip of a leaf or leaflet. drupe
A type of succulent fruit formed from one carpel; the single seed is enclosed by a stony
layer of the fruit wall, e.g. in peaches and olives. Also called a kernel. drupelet
A small drupe formed from one of the carpels in an apocarpous flower. Drupelets usually
form a compound fruit, as in Rubus, but they may become widely separated, as in Ochna. druse
A globular mass of calcium oxalate crystals, usually with the crystals radiating from an
organic core.==E==
-eae A
suffix added to the stem of a generic name to form the name of a tribe, e.g. Aster → Astereae. ebracteate
Lacking bracts. Synonymous with ebracteolate. ecological amplitude
The range of environmental conditions in which an organism can survive. edaphic
Influenced by or of the soil. elaiosome
An oily body attached to the seed. elephophily
A form of pollination whereby pollen or spores are distributed by the feet of elephants,
as in Rafflesia arnoldii. ellipsoid
A three-dimensional shape, elliptical in all sections through the long axis. elliptical (elliptic)
Planar, shaped like a flattened circle, symmetrical about both the long and the short axis, tapering
equally both to the tip and the base; oval. emarginate
Notched at the apex (notch usually broad and shallow). embryo
The young plant contained by a seed prior to germination. emergent
A plant taller than the surrounding vegetation or, for a water-based plant, one whose leaves
and flowers are above the water. enantiostyly
The condition in which the gynoecium protrudes laterally, to the right (dextrostyly) or to
the left (sinistrostyly) of the androecium. example: Senna. endemic
Having a natural distribution restricted to a particular geographic region. Compare native. endocarp
The innermost layer of the wall of a fruit; in a drupe, the stony layer surrounding the
seed. endodermis
The innermost layer of the cortex of vascular plant roots, also present in the stems of
pteridophytes. The radial walls are impregnated with suberin to form a permeability barrier
known as the Casparian strip. endophloeodal
See endophloic. endophloic
Of crustose lichens, having the thallus growing within rather than on the bark of trees. Compare
epiphloedal or corticolous (growing on the surface wood or bark) and endolithic (growing
within rock, not wood). endosperm
1. (angiosperms) A nutritive tissue surrounding the embryo of the seed, usually triploid,
originating from the fusion of both polar nuclei with one gamete after the fertilization
of the egg. 2. (gymnosperms) The prothallium within the
embryo sac. endospory
The production of spores that germinate into a reduced multicellular gametophyte contained
within the spore wall. Compare exospory. ensiform
Shaped like the blade of a sword. entire
1. Not divided. 2. (of a margin) Having a smooth margin, not
lobed or toothed (though possibly wavy or scalloped). entomophily
A form of pollination whereby pollen or spores are distributed by insects. ephemeral
Short-lived. See also caducous. epicalyx
An involucre resembling an outer calyx, e.g. as in Hibiscus. epicarp
The outer layer of the wall of a fruit, i.e. the “skin”. epicormic
Used to refer to buds, shoots or flowers developing from the old wood of trees, especially after
injury or fire. epicotyl
The part of the plant axis or stem between the cotyledonary node and the first foliage
leaves. epicuticular wax
A layer of crystalline or amorphous wax deposited on the surface of the cuticle. epidermis
An organ’s outermost layer of cells, usually only one cell thick. epigynous
Borne on the ovary; describes floral parts when attached above the level of the ovary
and arising from tissue fused to the ovary wall. Compare hypogynous and perigynous. epilithic
Growing on stone. Compare lithophytic, a plant growing on stone. epinecral
Dead tissue (necral) above the surface of the cortex of a lichen. epipetalous
Of stamens that are attached to the petals. epiphloedal
Growing on the surface of bark. Compare endophloedal (growing inside, not on, the bark) and epilithic
(growing on rock, not bark). epiphyte
A plant growing on another plant without deriving nourishment from it (in other words, not a
parasitic plant). Compare parasite. Often loosely and incorrectly applied to plants
that are not terrestrial (they may grown on various inorganic or organic surfaces), and
often to orchids, which are rock-dwelling (and therefore strictly lithophytic). epiphytic
Living on the surface of a plant. Compare lithophytic. epitepalous
Of stamens that are attached to the tepals. epithet
The adjectival component in a binomial; the final word or combination of words in a name
of more than one word (other than a term denoting rank) that denominates an individual taxon. epizoochory
A type of seed dispersal that occurs when seeds physically adhere to the outside of
vertebrate animal bodies. epruinose
Not pruinose. equitant
(of a leaf) Folded lengthwise and clasping another leaf. erect
Upright, more or less perpendicular to the ground or point of attachment. Compare patent
(spreading). Erecto-patent, between erect and patent. ericoid
Having leaves like those of the European heaths (Erica); small and sharply pointed. erose
(of a margin) Irregular as though nibbled or worn away. even-pinnate
Having an even number of leaflets in a compound leaf. Synonymous with paripinnate. evergreen
Not deciduous; having leaves all year. ex
In nomenclature, indicating that the preceding author proposed the name but did not legitimately
publish it, and that the succeeding author referred to the first author when legitimately
publishing the name. See Author citation (botany). exocarp
The outer layer of the pericarp, often the skin of fleshy fruits. exospory
The production of spores that germinate into free-living multicellular gametophytes. Compare
endospory. exotesta
The outer layer of the testa (seed coat). It is derived from the outer integument of
the ovule. exotic
Not native; introduced from another region or country. exserted
Projected beyond, e.g. stamens beyond the corolla tube. exstipulate
Lacking stipules. extrastaminal
Outside the stamens or androecium, usually referring to the location of a nectary disk. extrorse
Of anther locules, opening towards the outside of the flower. Compare introrse and latrorse.==F==
F1 hybrid A
single cross; a plant breeding term for the result of a repeatable cross between two pure
bred lines. F2 hybrid
A plant breeding term for the result of a plant arising from a cross between two F1
hybrids; may also refer to self-pollination in a population of F1 hybrids. fabiform
Shaped like a kidney bean. facultative
Of parasites, optional. Compare obligate. falcate
Curved like the blade of a scythe. family
A taxonomic group of one or more genera with features and/or ancestry in common; the term
for the principal rank between order and genus. farinaceous
Powderiness that is mealy fascicle
adj. fasciculate A cluster, e.g. a tuft of leaves all arising from the same node.
fasciculate Branching in clusters like a bundle of sticks
or needles; having fascicles. faveolate
Honeycombed; having regular, angled pits. Compare foveolate. faucal
Pertaining to the fauces; located in the throat of a calyx or corolla. fauces
The throat of a calyx or corolla; the conspicuously widened portion between the mouth and the
apex of the tube. In Boraginaceae, the site of distinctive appendages. felted
Covered with very dense, interlocked and matted hairs with the appearance or texture of felt
or woollen cloth. fenestrate
Having translucent areas. See also perforate, with holes. ferruginous
Ruddy or rust-colored. fertile
Capable of producing fruit; of flowers when they produce seed or of anthers containing
pollen. fertilization
The union of male and female gametes during sexual reproduction. fiber
1. A fiber cell. 2. Any flexible, strong, stringy, and very
elongate structure. fiber cell
a type of cell that is found in sclerenchyma, it is much elongated and dies soon after an
extensive modification of its cell wall. The cell wall is usually thickly lignified, but
is sometimes gelatinous. filament
1. stalk of a stamen 2. thread, one or a few cells thick. filamentous
consisting of filaments or fibres, hairlike. filiform
thread-like. e.g. stamen filaments, or leaf shapes. fimbria
slender hair-like process (plural: fimbriae) fimbriate
Fringed. fissure
A split or crack, often referring to fissured bark; a line or opening of dehiscence. fistule
A tube-shaped cavity. fistulose
Hollow; usually applied to a tube-shaped cavity, as in a reed. flabellate
Fan-shaped. flaccid
Limp; tending to wilt. Compare turgid. flexuous (flexuose)
Bent alternately in different directions; zig-zag. floccose
Having a soft and woolly covering of hairs. flora
1. all the plants growing in a certain region or country.
2. an enumeration of them, generally with a guide to their identification (e.g. the
present volume, the Flora of Victoria, the Flora of New South Wales and so on). In this
case ‘flora’ is written with a capital F. floral envelope
See perianth. floral leaves
The upper leaves at the base of the flowering branches. floral diagram
A graphical means to describe flower structure, usually a schematic cross-section through
a young flower. floral formula
A description of flower structure using numbers, letters and various symbols. floral tube
An imprecise term sometimes used as a synonym of hypanthium or of corolla tube or of calyx
tube. floret
A small flower, usually referring to the individual true flowers clustered within an inflorescence,
particularly those of the daisy and grass families. flower
The sexual reproductive structure of the Angiosperms, typically with a gynoecium, androecium, perianth
and an axis. foliate
Preceded by a number: having a certain number of leaflets; for example, 3-foliate, “having
three leaflets” foliicolous
A growth habit of certain lichens, algae, and fungi that prefer to grow on the leaves
of vascular plants. follicle
A dry fruit formed from one carpel, splitting along a single suture, to which the seeds
are attached. Compare pod (of legume). foliole
A small leaf-like appendage on the front or back. foliose
Leaflike; flattened like a leaf. forb
Any non-woody flowering plant that is not a grass, sedge or rush. forest
Vegetation dominated by trees with single trunks (including closely arranged trees with
or without an understory of shrubs and herbs). forma (in common usage, form)
A taxonomic category subordinate to species and within the taxonomic hierarchy, below
variety (varietas), and usually differentiated by a minor character. foveolate
Having regular tiny pits. Compare faveolate. free
Not united with other organs of the same type; not attached at one end. free central
Of placentation, ovules attached to a free-standing column in the centre of a unilocular ovary. frond
A leaf of a fern, cycad or palm. frutescent
Shrub-like (fruticose) or becoming shrub-like. fruticose
Shrubby; having the branching character of a shrub. fruit
A seed-bearing structure present in all angiosperms, formed from the mature ovary and sometimes
associated floral parts upon fertilization. fugacious
Disappearing, falling off, or withering. Compare persistent and caducous. funicle (funiculus)
The stalk of an ovule. funnelform
Having a form gradually widening from the base to apex; funnel-shaped. furcate
Forked, usually applied to a terminal division; with two long lobes. fused
Joined together. fusiform
Rod-shaped and narrowing gradually from the middle towards each end; spindle-shaped.==G==
galbulus (in gymnosperms) A fleshy cone (megastrobilus);
chiefly relates to those borne by junipers and cypresses and often mistakenly called
berries. gamete
A cell or nucleus that fuses with another of the opposite sex during sexual reproduction. gametophyte
The haploid multicellular phase in the alternation of generations of plants and algae that bears
gametes. In bryophytes the gametophyte is the dominant vegetative phase; in ferns and
their allies it is a small free-living plant known as the prothallus; in gymnosperms and
angiosperms the gametophytes are reduced to microscopic structures dependent on the sporophyte,
male gametophytes contained in pollen grains and females contained within the ovules. gene pool
The complete range of genetic variation found within a population. genus
pl. genera A group of one or more {{#species|species}} with features or ancestry (or both) in common.
Genus is the principal category of taxa intermediate in rank between family and species in the
standard nomenclatural hierarchy. generic name
The name of a taxonomic genus, such as Acacia and Eucalyptus. genotype
The genetic make-up of an individual. geophilous
Growing or rooting in the ground. germination
1. of seeds, describing the complex sequence of physiological and structural changes that
occur from resting to growth stage. 2. of a pollen grain; production of a pollen
tube when contacting a stigma receptive to it.
3. of a spore of fungi/bacterium; change of state – from resting to vegetative. gibbous (gibbose)
(of part of an organ) Swollen, usually with a pouch-like enlargement at the base. glabrescent
Becoming glabrous, almost glabrous. glabrous
1. Lacking surface ornamentation such as hairs, scales or bristles; smooth.
2. In lichenology, having no indumentum. gland
A secretory structure within or on the surface of a plant. glandular hair
A hair tipped with a gland. glaucous
Having a whitish bloom, blue-green in colour, e.g. the surface of the young leaves of many
eucalypts. globose
(also globular) Spherical. See also subglobose. globulose
Approximately spherical. glochid
A tiny barbed hair or bristle, e.g. the fine hairs in Opuntia. glumes
bracts subtending the floret(s) of a sedge, or similar plant; in grasses forming the lowermost
organs of a spikelet (there are usually 2 but 1 is sometimes reduced; or rarely, both
are absent). glutinous
Sticky. graft
1. The artificial union of plant parts. 2. A plant shoot suitable for grafting; loosely,
a scion, sucker or branch. graft chimaera (sometimes graft hybrid)
A taxon whose members consist of tissue from two or more different plants in intimate association
originated by grafting. The addition sign “+” is used to indicate a graft-chimaera either
as a part of a formula (e.g. Crataegus monogyna + Mespilus germanica) or in front of an abbreviated
name (e.g. +Crataegomespilus ‘Dardari’). The nomenclature of graft hybrids is governed
by the International Code of Nomenclature for Cultivated Plants. graminoid granular
(of a surface) Covered with small rounded protuberances. grass
A plant belonging to the family Poaceae. grassland
Low vegetation dominated by grasses. groundcover
1. Dense vegetation that covers the ground. 2. A term applied to describe a plant that
covers the soil surface so densely that it smothers all beneath it. group
A formal category equivalent to or below the rank of genus which distinguishes:
an assemblage of two or more cultivars within a species or hybrid;
plants derived from a hybrid in which one or more of the parent species is not known
or is of uncertain origin; a range of cultivated plants of a species
or hybrid which may exhibit variation but share one or more characters, which makes
it worth distinguishing them as a unit. guard cell
Each of two cells surrounding the stoma which control gas exchange between the apoplast
of the plant and the external environment. guttate
Having droplet-shaped spots. Compare punctate and maculate. guttation
The secretion of liquid water from uninjured plant parts. See hydathode. guttulate
Having or appearing to be spotted with oil droplets; of spores, having oil droplets inside. gymnosperm
A seed-bearing plant with unenclosed ovules borne on the surface of a sporophyll. Gymnosperms
are among the oldest clades of vascular plants, and today are represented by approximately
1,000 extant species worldwide, including, among others, conifers, Ginkgo, Gnetum and
cycads. Compare angiosperm. gynobasic
Of a style, arising near the base of the gynoecium, e.g. between the lobes of the ovary. gynodioecious
Of a species, with some plants bearing only bisexual flowers and others bearing only female
flowers. gynomonoecious
Of a species, with bisexual flowers and female flowers on the same plant. gynoecium
The collective term for the female parts of a flower or for the carpels of a flower, whether
united or free. Compare androecium. Abbreviation: G. For instance, G indicates a superior ovary;
G(5) indicates having five fused carpels. gynophore
A stalk supporting the gynoecium and situated above the level of insertion of the other
floral parts.==H==
habit The general external appearance of a plant,
including size, shape, texture and orientation. habitat
The place where a plant lives; the environmental conditions of its home. hafter
A flat attachment that forms when the thallus of a fruticose or foliose lichens comes in
contact with a substrate, different from rhizines and hapters. hair
A single elongated cell or row of cells borne on the surface of an organ. half-inferior
Of ovary, partly below and partly above the level of attachment of the other floral parts.
Compare inferior, superior. halonate
Having a transparent coating, or being of a spore’s outer layer. halophyte
A plant adapted to living in highly saline habitats; a plant that accumulates high concentrations
of salt in its tissues. hand-pollination
The controlled act of pollination that excludes the possibility of open-pollination. haploid
Having one set of chromosomes, e.g. the complement of chromosomes in each of the cells of the
gametophyte, the nucleus of a gamete and the spores. This is expressed symbolically as
n, where n=the gametic number of chromosomes. Compare diploid, triploid, and tetraploid. hapter
An attachment that may form when a foliose lichen thallus comes in contact with a substrate. hastate
Triangular in outline, the basal lobes pointing outwards, so that the base appears truncate;
may refer only to the base of a leaf with such lobes. Compare sagittate which refers
to basal lobes pointing backwards. haustorium
In parasitic plants, a structure developed for penetrating the host’s tissues. head
See capitulum, a pseudanthium. heathland
Vegetation dominated by small shrubs which usually have ericoid leaves. helicoid
Coiled; of a cymose inflorescence, when the branching is repeatedly on the same side (the
apex is often recurved). Compare scorpioid. hemi-legume
A legume fruit in which the seed or seeds and one valve of the pod are dispersed as
a unit. The valve catches the wind and blows away with the seeds, as in Acaccia tenuifolia,
Peltogyne paniculata. herb
Any vascular plant that does not develop a woody stem at any point during its life cycle,
e.g. a violet. herbaceous
Not woody; usually green and soft in texture. herbarium
pl. herbaria A collection of preserved, usually pressed and dried, plant material used for
identification and comparison; also a building in which such collections are stored.
hermaphrodite A synonym of bisexual. heteroblastic
Having parts, especially leaves, that are distinctly different between the juvenile
and adult stages. heteromorphic
Having two or more distinct morphologies (e.g. of different size and shape). heterospory
The production of spores of two different sizes (small and large) by the sporophytes
of land plants. heterostyly
The condition of a species having flowers with different style and stamen lengths, but
with all the flowers of any one plant being identical. see:distyly hilum
The scar on a seed coat where it separates from its stalk (funicle). hip
The fruit of a rose plant. hippocrepiform
Horseshoe-shaped. hirsute
Bearing coarse, rough, longish hairs. See indumentum. hispid
Bearing long, erect, rigid hairs or bristles, harsh to touch. hoary
Covered with a greyish to whitish layer of very short, closely interwoven hairs, giving
a frosted appearance. holotype
A type chosen by the author of a name. Compare lectotype. homochlamydeous
Perianth not divided into calyx and corolla. Compare dichlamydeous. hort.
(never capitalised) Of gardens, an author citation used in two ways:
as a name misapplied by gardeners 2. as an invalid name derived from horticultural
writings of confused authorship. hyaline
Translucent; usually delicately membranous and colourless. hybrid
A plant produced by the crossing of parents belonging to two different named groups, e.g.
genera, species, varieties, subspecies, forma and so on; i.e. the progeny resulting within
and between two different plants. An F1 hybrid is the primary product of such a cross. An
F2 hybrid is a plant arising from a cross between two F1 hybrids (or from the self-pollination
of an F1 hybrid). hybrid formula
The names of the parents of a hybrid joined by a multiplication sign, e.g. Cytisus ardonoi
× C. purgans. hydrophily
A form of pollination whereby pollen is distributed by the flow of waters. hypanthium
A tube or cup-like structure in a flower that includes the bases of sepals, petals, and
stamens, and may or may not be connected (adnate) to the ovary. hyper-resupinate
In botany, describing leaves or flowers that are in the usual position, but are borne on
a petiole or pedicel, respectively, that is twisted 360 degrees. The term is used to describe
organs, such as orchid flowers, that are usually resupinate. Compare #resupinate. hypocarpium
An enlarged fleshy structure that forms below the fruit, from the receptacle or hypanthium. hypocotyl
Of an embryo or seedling, the part of the plant axis below the cotyledon and node, but
above the root. It marks the transition from root to stem development. hypocrateriform
See salverform. hypogynous
Borne below the ovary; used to describe floral parts inserted below the ovary’s level of
insertion. Compare epigynous, perigynous. hypothallus
The hypothallus is the outgrowth of hyphae from under the margin of the thallus of a
crustose lichens, connecting the island-like areoles into a single lichen. hysteranthous
A type of growth in which new leaves appear after flowering. Also spelled histeranthous.
Compare proteranthous and synanthous.==I==
idioblast A cell, especially of a leaf, differing markedly
from surrounding cells. They often synthesise specialised products such as crystals. illegitimate name (nomen illeg.)
A name not abiding by the rules of the botanical Codes, e.g. later homonyms, cultivars that
have been Latinised after 1 Jan 1959; cultivar names with more than 10 syllables or 30 letters;
cultivar names that use confusing names of other plants, e.g. Camellia ‘Rose’. imbricate
Overlapping each other; of perianth parts, edges overlapping in the bud (the convoluted
arrangement is a special form of imbrication). imparipinnate
A pinnate leaf with an odd number of pinnae (terminated by a single leaflet). Compare
paripinnate. in
In nomenclature, where the preceding author published the name in an article or book,
authored or edited by the succeeding author. -inae
The suffix added to the stem of a generic name to form the name of a subtribe: for instance,
Corydalinae from Corydalis + -inae. inbreeding
The production of offspring between closely related parents leading to a high degree of
similarity; self-fertilization is the most intense form of inbreeding. incertae sedis
Of unknown taxonomic affinity; relationships obscure. incised
Cut deeply and (usually) unevenly (a condition intermediate between toothed and lobed). included
Enclosed, not protruding, e.g. stamens within the corolla. incurved
Bent or curved inwards; of leaf margins, when curved towards the adaxial side. ined.
An abbreviation of Latin inedita, an unpublished work. Used to indicate that a botanical name
appeared only in a manuscript that was not published, so the name is invalid. indefinite
variable in number; numerous, e.g. more than twice as many stamens as petals or sepals,
or when an inflorescence is not terminated by a flower (and continues growing). Compare
definite. indehiscent
not opening in any definite manner at maturity; usually referring to fruit. Contrast with
dehiscent. indeterminate
unlimited, usually in growth. indigenous
native to the area, not introduced, and not necessarily confined to the region discussed
or present throughout it (hardly distinct from ‘native’ but usually applied to a
smaller area). For example, the Cootamundra Wattle is native to Australia but indigenous
to the Cootamundra region of southern New South Wales. Compare endemic. indumentum
a collective term for a surface covering of any kind of trichomes, e.g. hairs, scales. induplicate
folded upwards, or folded with the two adaxial surfaces together. indusium
1. a membrane covering the sporangia of some ferns.
2. a cup enclosing the stigma in Goodeniaceae. inferior
of an ovary, at least partly below the level of attachment of other floral parts. Compare
superior. inflated
swollen, like a bladder. inflexed
bent sharply upwards or forwards. Compare deflexed. inflorescence
several flowers closely grouped together to form an efficient structured unit; the grouping
or arrangement of flowers on a plant. infraspecific
denotes taxonomic ranks below species level, for example subspecies. infrageneric
denoting taxonomic ranks below the genus level, for example, subgenera, sections, and series. infructescence
the grouping or arrangement of fruits on a plant. wikt:infundibular (infundibuliform)
funnel-shaped, for example in the corolla of a flower. inrolled
rolled inwards. insectivorous
catching, and drawing nutriment from, insects. insertion, point of
the point at which one organ or structure (such as a leaf) is joined to the structure
which bears it (such as a stem). inserted
growing out from integument
in general, any covering, but especially the covering of an ovule. intercalary
(e.g. of growth) occurring between the apex and the base of an organ intercalary meristem
a meristem located between the apex and the base of an organ interjugary glands
in pinnate leaves, glands occurring along the leaf rachis between the pinnae (occurring
below the single, and often slightly larger, gland at or just below the insertion of the
pinnae). Compare jugary. internode
the portion of a stem between two nodes. interpetiolar
of stipules, between the petioles of opposite leaves, e.g in Rubiaceae. intramarginal
inside but close to the margin, for example a vein in a leaf. intrastaminal
inside the stamens or androecium, usually referring to the location of a nectary disk. introrse
of anther locules, with opening towards the centre of flower (at least in bud). Compare
extrorse, latrorse. invalid
Use of names not validly published according to the Code, i.e. they are not strictly ‘names’
in the sense of the International Code of Botanical Nomenclature. involucre
A structure surrounding or supporting, usually a head of flowers. In Asteraceae, it is the
group of phyllaries (bracts) surrounding the inflorescence before opening, then supporting
the cup-like receptacle on which the head of flowers sits. In Euphorbiaceae it is the
cuplike structure that holds the nectar glands, nectar, and head of flowers, and sits above
the bract-like cyathophyll structure. Involucres occur in Marchantiophyta, Cycads, fungi, and
many other groups. involute
Rolled inwards, for example when the margins of a leaf are rolled towards the adaxial (usually
upper) surface. Compare revolute. iridescent
Having a reflective coloured sheen produced by structural coloration, as in the speculum
of the mirror orchid Ophrys speculum. irregular
Not able to be divided into two equal halves through any vertical plane. See also asymmetrical.
Compare zygomorphic, actinomorphic, and regular. isidium
pl. isidia A warty of club-like structure in some lichens that breaks off and forms
new lichens without sexual reproduction. Isidia are dispersed by mechanical means, compared
to soredia, which are dispersed by wind. isobifacial
(of flat structures, especially leaves) Having both surfaces similar, usually referring to
cell types or to the number and distribution of stomata. isomerous
Having an equal number of parts in the whorls. isotomic
Having branches of equal diameter. Compare anisotomic.==J==
joint A node or junction of two parts; articulation. jugary
A gland occurring on the rachis of a bipinnate leaf at the junction or attachment of pairs
of pinnae or pinnules, as in some Acacia species. Compare interjugary. juvenile leaves
Leaves formed on a young plant and different in form from the adult leaves.==K==
K, K+, K- In lichenology, “K” is the abbreviation for
the outcome of a test in which a 10% solution of potassium hydroxide (KOH — hence “K”)
is placed on lichen tissues. Color change is noted by “K-” for none, and K+ for a yellow
to red or purple color. keel
adj. keeled A prominent longitudinal ridge like the keel of a boat, e.g. the structure
of the corolla formed by the fusion of the lower edge of the two abaxial anterior petals
of flowers in the Fabaceae. kernel
See drupe. key innovation
A novel phenotypic trait that allows subsequent evolutionary radiation and success of a taxonomic
group. kingdom
the highest generally employed category of the taxonomic hierarchy, above that of division
(phylum). The Plant Kingdom includes vascular plants, bryophytes and green algae and is
also known as the clade Viridiplantae. Klausenfrucht
Klausen or Klausenfrucht (german) is a special type of fruits in Lamiaceae and Boraginaceae.
A dry, dehiscent fruit formed from a superior ovary with axil or basal placentation, with
an adherent calyx, from more than one carpel and usually breaking apart into 1-seeded units
by separating each carpel by false septa. One unit is a half carpel, mostly there are
four units, seeds. English therms are eremocarp, schizocarp, mericarp or nutlets.==L==
labellum lip; one of three or five petals which is
(usually) different from the others, e.g. in Orchidaceae and Stylidiaceae. labiate
lipped; where a corolla is divided into two parts, called an upper and lower lip, the
two resembling an open mouth with lips. lacerate
jagged, as if torn. lacinia
In foliose lichens, a linear to elongate lobe, usually arising from or at the end of a larger
lobe laciniate
Of lobes – with ends irregularly divided into deeply divided, narrow, pointed segments;
Of margins – deeply divided into pointed segments in an irregular manner. lacuna
An empty space, hole, cavity, pit, depression, or discontinuity. lamella
a thin, plate-like layer. (plural lamellae; adjective lamellate – composed of an assemblage
of many layers) lamina
the blade of a leaf or the expanded upper part of a petal, sepal or bract. laminal
of, or pertaining to, the upper surface, such as the cortex of a lichen. lanceolate
longer than broad, narrowly ovate, broadest in the lower half and tapering to the tip,
like a lance or spear head; (sometimes, and incorrectly, used to mean narrowly elliptic). lateral
attached to the side of an organ, e.g. leaves on a stem. latex
a milky fluid that exudes from such plants such as spurges, figs and dandelions. laticiferous
latex-bearing, producing a milky juice. latrorse
a type of anther dehiscence in which the anthers open laterally toward adjacent anthers. cf.
introrse, extrorse. lauroid
resembling Laurus, the laurel genus, particularly its leaves. lax
loose, not compact. Of bundles of hyphae in lichens – not stiff and not adglutinate. leaf
an outgrowth of a stem, usually flat and green; its main function is food manufacture by photosynthesis.
Abbreviation: lvs. leaf gap
a parenchymatous area in the stele above (distal to) a leaf trace. leaf scar
a healing layer forming on the stem where the leaf has fallen off. leaf trace
A vascular bundle connecting the stele to a leaf. leaflets
The ultimate segments of a compound leaf. lecanorine
of lichens, having apothecia with rims of tissue similar to the tissue of the thallus,
as in the genus Lecanora legume
1. a fruit characteristic of the family Fabaceae, formed from one carpel and either dehiscent
along both sides, or indehiscent. 2. a crop species in the family Fabaceae.
3. a plant belonging to the Fabaceae family. lemma
the lower of 2 bracts enclosing a grass flower. lenticel
Typically lens-shaped (lenticular) porous tissue in bark with large intercellular spaces
that allows direct exchange of gases between the internal tissues and atmosphere through
the bark. lenticular
1. lens-shaped. 2. covered in lenticels lepidote
covered with small scales. leprose
powdery liana
a woody climbing plant, rooted in the ground (liane is also used). liane
a woody climbing plant, rooted in the ground. See also liana. lichenicolous
growing on or in lichens, often but not necessarily as parasites ligneous
having hard lignified tissues or woody parts, woody lignum
Dead wood, typically in the context of a substrate for lichens. lignicolous
Growing on wood tissue after bark as fallen or been stripped off (compare to corticolous) lignotuber
a woody swelling of the stem below or just above the ground; contains adventitious buds
from which new shoots can develop, e.g. after fire. ligulate
1. bearing a ligule. 2. strap-shaped. ligule
1. small membranous appendage on the top of the sheath of grass leaves.
2. a minute adaxial appendage near the base of a leaf, e.g. in Selaginella.
3. extended, strap-like corolla of some daisy florets. linea, line, British line, Paris line
various pre-metric units somewhat larger than 2 mm, used in botany into the 20th century.
See Line (unit) and Paris line. linear
very narrow in relation to its length, with the sides mostly parallel. See Leaf shape. lithophytic
a plant growing on rocks; an epilithic plant. lobe
part of a leaf (or other organ), often rounded, formed by incisions to about halfway to the
midrib. loculicidal
of a fruit, when it dehisces through the centres of loculi. Compare septicidal. locule
a chamber or cavity containing seeds within an ovary, pollen within an anther or spores
in a sporangium. lodicule
one of 2 or three minute organs at the base of the ovary of a grass flower, representing
parts of a strongly reduced perianth. lomentum
a pod-like indehiscent fruit that develops constrictions between the segments and at
maturity breaks into one-seeded segments. longicidal
(anthers) opening lengthwise by longitudinal slits. compare: poricidal lunate
crescent-shaped. lumen
the cavity bounded by a plant cell wall. lyrate
lyre-shaped; deeply lobed, with a large terminal lobe and smaller lateral ones.==M==
maculate spotted, marked with spots. Malesia
a biogeographic region comprising Malaysia, Indonesia, New Guinea, and the Philippines. mallee
growth habit in which several woody stems arise separately from a lignotuber; a plant
with such a growth habit, e.g. many Eucalyptus species; vegetation characterized by such
plants. mangrove
a shrub or small tree growing in salt or brackish water, usually characterized by pneumatophores.
Tropical coastal vegetation characterized by such species. margin
the edge, as in the edge of a leaf blade. marginal
occurring at or very close to the margin. marsh
a waterlogged area; swamp. mast
edible fruit and nuts produced by woody species of plants, i.e. acorns and beechmast, that
wildlife species and some domestic animals consume. mealy
covered with coarse, floury powder. medulla
1. In a lichen, the typically undifferentiated tissue underneath the cortex of the thallus,
or between the upper and lower cortex if both are present. The medulla is analogous to the
tissues underneath the epidermis (skin) of a leaf. The uppermost region commonly contains
most of the photobionts. 2. pith. See also medullary rays in wood. megasporangium
the larger of two kinds of sporangium produced by heterosporous plants, producing large spores
that contain the female gametophytes. Compare microsporangium. megaspore
the larger of two kinds of spores produced by a heterosporous plant, giving rise to the
female gametophyte. Compare microspore. megasporophyll
in hetersoporous plants, a modified leaf bearing one or more megasporangia. Compare microsporophyll. megastrobilus
the larger of two kinds of cones or strobili produced by gymnosperms, being female and
producing the seeds. Compare microstrobilus. membranous
thin, translucent and flexible, seldom green. mericarp
one segment of a fruit (a schizocarp) that splits at maturity into units derived from
the individual carpels, or a carpel, usually 1-seeded, released by the break-up at maturity
of a fruit formed from 2 or more joined carpels. meristem
an actively dividing tissue. mesic
moist, avoiding both extremes of drought and wet; pertaining to conditions of moderate
moisture or water supply; applied to organisms (vegetation) occupying moist habitats. mesocarp
The fleshy portion of the wall of a succulent fruit inside the skin and outside the stony
layer (if any), surrounding the seed(s); sarcocarp. mesomorphic
Soft and with little fibrous tissue, but not succulent. mesophyll
1. Mesophyll tissue, photosynthetic tissue of a leaf, the central tissues between the
upper and lower epidermis. 2. In ecology, the blade of a leaf or leaflet
that has a surface area 4500–18225 mm2; A plant, or vegetation, that has mesophyll
(sized) leaves. mesophyllous
(of vegetation) Of moist habitats and having mostly large and soft leaves. mesophyte
A plant thriving under intermediate environmental conditions of moderate moisture and temperature,
without major seasonal fluctuations. microsporangium
The smaller of two kinds of sporangium produced by a heterosporous plant, producing microspores
that contain the male gametophyte. Compare megasporangium. microspore
The smaller of two kinds of spores produced by a heterosporous plant. Compare megaspore. microsporophyll
In heterosporous plants, a modified leaf bearing one or more microsporangia. Compare megasporophyll. microstrobilus
The smaller of two kinds of cones or strobili produced by gymnosperms, being male and producing
the pollen. Compare megastrobilus. midrib
The central and usually most prominent vein of a leaf or leaf-like organ. Also called
the midvein. midvein
see midrib. monad
A single individual that is free from other individuals, not united with them into a group.
The term is usually used for pollen to distinguish single grains from tetrads or polyads. moniliform
Resembling a string of beads. monocarpic
Flowering and setting seed only once before dying. See also semelparous. monochasium
A cymose inflorescence with the branches arising singly. Compare dichasium. monocot
An abbreviation of monocotyledon. monocotyledon
A flowering plant whose embryo contains one cotyledon (seed-leaf). Compare dicotyledon. monoecious
Of vascular plants, hermaphroditic, with all flowers bisexual; or with male and female
reproductive structures in separate flowers but on the same plant; or of an inflorescence
that has unisexual flowers of both sexes. Compare dioecious. monoicous
Of bryophyte gametophytes, hermaphroditic, bisexual, when both male and female reproductive
structures develop on the same individual. Compare dioicous. monograph
of a group of plants, a comprehensive treatise presenting an analysis and synthesis of taxonomic
knowledge of that taxon; the fullest account possible (at the time) of a family, tribe
or genus. It is generally worldwide in scope and evaluates all taxonomic treatments of
that taxon including studies of its evolutionary relationships with other related taxa, and
cytological, genetic, morphological, palaeobotanical and ecological studies. The term is often
incorrectly applied to any systematic work devoted to a single taxon. Compare revision. monomorphic
of one type, rather than several. See also dimorphic (two types) and polymorphic (many
types) monophyllous
Having a single leaf. monopodial
a mode of stem growth and branching in which the main axis is formed by a single dominant
meristem. monostromatic
Being a single cell thick, as in the alga Monostroma. monotypic
containing only one taxon of the next lower rank, e.g. a family with only one genus, or
a genus that includes only a single species. morphology
the shape or form of an organism or part thereof. mucro
Diminutive: mucronule. A sharp, short point, generally at the tip of a leaf or the tip
of the midrib of a compound leaf. mucronate
terminating in a mucro. multiple fruit
a cluster of fruits produced from more than one flower and appearing as a single fruit,
often on a swollen axis, as in Moraceae. Compare aggregate fruit. muricate
covered with short hard protuberances. mutation
an abrupt and inexplicable variation from the norm, such as the doubleness in flowers,
changes in colour, or habit of growth. mycobiont
The fungal component of a lichen (compare to photobiont. mycelium
The “vegetative” (nonreproductive) part of a fungus, mostly composed of aggregations
of hyphae. It functions in substrate decomposition and absorption of nutrients. mycobiont
The fungal component of a lichen (compare to photobiont. mycorrhiza
adj. mycorrhizal One of several types of symbiotic association between a fungus and the roots
of a plant. mycotroph
adj. mycotrophic A plant that obtains most or all of its carbon, water and nutrients
by associating with a fungus.==N==
native naturally occurring in an area, but not necessarily
confined to it. Compare endemic. natural hybrid
A hybrid taxon produced by chance in the wild. naturalised
Describing a plant, introduced from another region, that grows and reproduces readily
in competition with the natural flora. nectar
A usually sweet, nutrient-rich fluid produced by the flowers of many plants and collected
by bees and other insects. nectary
adj. nectariferous A specialized gland that secretes nectar.
neophyte A plant that has recently been introduced
to a geographic area. Compare archaeophyte. nerve
A synonym of vein. node
The part of a stem from which leaves or branches arise. nomen conservandum
(Latin) A conserved name, usually a name that became so much better known than the correct
name, that a substitution was made. nomen illegitimum
(Latin) A name that is either superfluous at its time of publication because the taxon
to which it was applied already has a name, or the name has already been applied to another
plant (a homonym). nomen invalidum
(Latin, see valid publication) A name that is not validly published, and technically
is therefore not a botanical name. (Abbreviation: nom. inval.) nomen nudum
(Latin) A name not published in accordance with the International Code of Nomenclature
for algae, fungi, and plants, usually without a diagnosis or description of the entity to
which it applies, and without reference to either; such a name should not be used. nomenclature
The naming of things; often restricted to the correct use of scientific names in taxonomy;
a system that sets out provisions for the formation and use of names. noxious
Of plants, containing harmful or unwholesome qualities. Applied in conjunction with ‘weed’
to specifically describe a plant which legislation deems harmful to the environment. Each state
and territory in Australia has specific legislation governing noxious weeds. nucellus
The tissue of the ovule of a seed plant that surrounds the female gametophyte. It is enclosed
by integuments and is not of epidermal origin. numerous
Stamens are described as numerous when there are more than twice as many as sepals or petals,
especially when there is no set number of them. nut
A hard, dry, indehiscent fruit containing only one seed. nutlet
A small nut; one of the lobes or sections of the mature ovary of some members of the
Boraginaceae, Verbenaceae, and Lamiaceae.==O==
ob- A prefix meaning “inversely”; usually the
same shape as that described by the word stem, but attached by the narrower end. See obcordate,
oblanceolate and obovate. obconic
(of a fruit, hypanthium, pistil or calyx) Shaped like an inverted cone, attached at
the apex. obcordate
(of a leaf blade) Broad and notched at the tip; heart-shaped but attached at the pointed
end. obdiplostemonous
Having stamens arranged in two whorls, and having twice as many stamens as petals, with
the outer whorl being opposite the petals. Compare diplostemonous. oblanceolate
Having a lanceolate shape but broadest in the upper third. obligate
(of parasites) Unable to survive without a host. Compare facultative. oblique
slanting; of a leaf or stem, larger on one side of the midrib than the other, in other
words asymmetrical. obloid
Having a three-dimensional oblong shape, e.g. a fruit. oblong
Having a length a few times greater than the width, with sides almost parallel and ends
rounded. obovate
(of a leaf) Having a length about 1.5 times the width, and widest above the centre. obsolete
Not evident, or at most rudimentary or vestigial. obtuse
Blunt or rounded; having converging edges that form an angle of more than 90°. Compare
acute. ocrea
Also spelled ochrea. A sheath formed from two stipules encircling the node in members
of the Polygonaceae. odd-pinnate
Also imparipinnate. Having an odd number of leaflets in a compound leaf, such that there
is only one terminal leaflet. oft.
An abbreviation of “often”. Compare usu. and s.t. -oideae
A suffix added to the stem of a generic name to form the name of a subfamily, e.g. Fumaria
→ Fumarioideae. olim
Formerly, e.g. “olim B”, formerly in the Berlin herbarium (Herbarium Berolinense). ontogeny
The sequence of developmental stages through which an organism passes. opus utique oppressum
pl. opera utique oppressa Listed after the botanical name of a plant, or the name of
a publication, this indicates that a publication is listed in the International Code of Nomenclature
for algae, fungi, and plants as a suppressed work. Botanical names of the specified rank
in the publication are considered not validly published (article 34).
operculum (calyptra) A lid or cover that becomes detached at maturity,
e.g. in Eucalyptus, a cap covering the bud and formed by the fusion or cohesion of perianth
parts. opposite
1. Describing leaves or flowers borne at the same level but on directly opposite sides
of their common axis. 2. Describing the occurrence of something
on the same radius as something else, e.g. anthers opposite sepals. Compare alternate. orbicular
Flat and more or less circular. order
A group of one or more families sharing common features, ancestry, or both. ortet
The original single parent plant from which a clone ultimately derives. orthotropous
When an ovule is erect, with the micropyle directed away from the placenta; atropous.
Compare amphitropous, anatropous, campylotropous. oval
see elliptical. ovary
the basal portion of a carpel or group of fused carpels, enclosing the ovule(s). ovate
shaped like a section through the long-axis of an egg and attached by the wider end. ovoid
egg-shaped, with wider portion at base; 3-dimensional object, ovate in all sections through long-axis. ovule
loosely, the seed before fertilization; a structure in a seed plant within which one
or more megaspores are formed (after fertilization it develops into a seed).==P==
pachycaul with a disproportionately thick trunk pachycladous
with disproportionately thick stems palea
(plural paleae) 1. the upper of two bracts enclosing a grass
flower, major contributors to chaff in harvested grain.
2. Chaffy scales on the receptacles of many Asteraceae.
3. Chaffy scales on the stipe of many ferns. paleate
bearing paleae or chaffy scales, as in description of the receptacle of a capitulum of a plant
in the Asteraceae. paleaceous
Chaff-like in texture. palmate
1. leaf with veins radiating out from a central point (usually at the top of a petiole), resembling
spread out fingers pointing away from the palm.
2. A compound palmate leaf has leaflets that radiate from a central point (usually at the
top of a petiole). palmatifid
Deeply divided into several lobes arising from more or less the same level. palmatisect
Intermediate between palmate and palmatifid, i.e. the segments are not fully separated
at the base; often more or less digitate. panicle
adj. paniculate A compound raceme; an indeterminate inflorescence in which the flowers are borne
on branches of the main axis or on further branches of these.
papilionate Butterfly-like; having a corolla like that
of a pea. papilla
pl. papillae; adj. papillose, papillate A small, elongated protuberance on the surface
of an organ, usually an extension of one epidermal cell.
pappus in daisy florets, a tuft or ring of hairs
or scales borne above the ovary and outside the corolla (representing the reduced calyx);
a tuft of hairs on a fruit. paraperigonium
Also paraperigone. Anomalous secondary outgrowth of the perianthal meristem with ramifying
vasculature. See also perigonium, perianth and coronaparasite
An organism living on or in a different organism, from which it derives nourishment. Some plant
species are parasitic. Compare saprophyte and epiphyte. parenchyma
A versatile ground tissue composed of living primary cells which performs a wide variety
of structural and biochemical functions in plants. parietal
Attached to the marginal walls of a structure, e.g. ovules attached to placentas on the wall
of the ovary. See placentation. paripinnate
Having an even number of leaflets (or pinnae), i.e. terminated by a pair of pinnae as opposed
to a single pinna. Compare imparipinnate. parthenocarpy
The development or production of fruit without fertilization. Compare stenospermocarpy. patent
Spreading, standing at 45–50° to the axis. See also erecto-patent and patulous. patulous
See patent. pauciflor
Having few flowers per inflorescence. Compare pluriflor and uniflor. pectinate
Pinnately divided with narrow segments closely set like the teeth of a comb. pedate
Having a terminal lobe or leaflet, and on either side of it an axis curving outwards
and backwards, bearing lobes or leaflets on the outer side of the curve. pedicel
adj. pedicellate The stalk of a flower; may also be applied to the stalk of a capitulum
in the Asteraceae. peduncle
(adj. pedunculate) the stalk of an inflorescence. peltate
shield-like; with stalk attached to the lower surface and not to the margin. pellucid
transmitting light; for example, said of tiny gland dots in the leaves of e.g. Myrtaceae
and Rutaceae that are visible when held in front of a light. pendulous
hanging, for example an ovule attached to a placenta on the top of the ovary. Compare
suspended. penicillate
tufted like an artist’s brush; with long hairs towards one end. penninervation (penninerved)
with pinnately arranged veins. pentamerous
in five parts, particularly with respect to flowers, five parts in each whorl. See also
trimerous and tetramerous. pepo
type of berry formed from an inferior ovary and containing many seeds, usually large with
a tough outer skin, for instance, pumpkin, cucumber. perennating
of an organ that survives vegetatively from season to season. A period of reduced activity
between seasons is usual. perennial
a plant whose life span extends over several years. perfect
of a flower, when bisexual. perfoliate
with its base wrapped around the stem (so that the stem appears to pass through it),
e.g. of leaves and bracts. perforate
with many holes. Used to describe the texture of pollen exine, and also to indicate that
tracheary elements have a perforation plate. See also fenestrate. perforation plate
in a tracheary element, part of the cell wall that is perforated; present in vessel members
but not in tracheids. Should not be confused with a pit. perianth
the collective terms for the calyx and corolla of a flower (generally used when the two are
similar). Abbreviation: P. For instance P 3+3 indicates the calyx and corolla each have
3 elements, or 3 sepals + 3 petals pericarp
the wall of a fruit, developed from the ovary wall. periclinal
Curved along parallel to a surface. Compare anticlinal. pericycle
a cylinder of parenchyma or sclerenchyma cells that lies just inside the endodermis and is
the outer most part of the stele of plants. perigonium
in flowering plants see perianth 2. in mosses, the leaves surrounding the antheridia,
also called a spash-cup, e.g. in Polytrichum juniperinum. perigynium
a sac from a modified tubular bract, or when fully closed an utricle, around the pistillate
flower of sedges perigynous
borne around the ovary, i.e. of perianth segments and stamens arising from a cup-like or tubular
extension of receptacle (free from the ovary but extending above its base). Compare epigynous,
hypogynous. persistent
remaining attached to the plant beyond the usual time of falling, for instance sepals
not falling after flowering, flower parts remaining through maturity of fruit. Compare
deciduous, caducous. perule
(adj. perulate) 1. the scales covering a leaf or flower bud,
or a reduced scale like leaf surrounding the bud. Buds lacking perulae are referred to
as ‘naked’ 2. in Camellias the final bracts and sepals
become indistinguishable and are called perules. 3. a kind of sac formed by the adherent bases
of the two lateral sepals in certain orchids. petal
in a flower, one of the segments or divisions of the inner whorl of non-fertile parts surrounding
the fertile organs, usually soft and conspicuously coloured. Compare sepal. petaloid
like a petal; soft in texture and coloured conspicuously. petiolate
a leaf with a petiole. Compare sessile. petiole
the stalk of a leaf. petiolule
the stalk of a leaflet. petricolous
Rock-dwelling; living on or among rocks. phaneranthous
showy, as in showy flowers that advertise to pollinators, as opposed to aphananthous
(unshowy) phanerogam
gymnosperms and angiosperms; plants producing stamens and gynoecia; literally plants with
conspicuous sexual reproductive organs. Compare cryptogams. phenology
the study of the timing of seasonal biological phenomena, such as flowering, leaf emergence,
fruit ripening and leaf fall. phloem
a specialised conducting tissue in vascular plants that transports sucrose from the leaves
to other plant organs. photobiont
In a lichen, the component that does the photosynthesis, the green algae (Chlorophyta) or blue-green
algae (Cyanobacteria). (compare to mycobiont, the fungal component.) Also called the phycobiont. photosynthesis
The process by which energy from sunlight is used to convert carbon dioxide and water
into simple sugars in cells containing chloroplasts. All plants, except certain parasites, can
perform photosynthesis. phycobiont
In a lichen, a synonym for photobiont phyllary
An individual bract within an involucre or involucel. phyllid
A leaf-like extension of the stem in Bryophytes phyllode
adj. phyllodineous A leaf with the blade much reduced or absent, and in which the petiole
and or rachis perform the functions of the whole leaf, e.g. many acacias. Compare cladode.
phyllopodium (in ferns) A short outgrowth of the stem on
which the frond is borne and which remains attached to the rhizome after the frond has
been shed. phyllosphere
The above-ground surface of plants as a habitat for epiphytic microorganisms. phytomelan
Also phytomelanin; adj. phytomelanous A black, inert, organic material that forms a crust-like
covering of some seeds, commonly found in Asparagales, Asteraceae, etc.
pilose covered with soft, weak, thin and clearly
separated hairs, which are usually defined as long and sometimes ascending. pinna
(plural pinnae) a primary segment of a compound leaf. pinnate
a compound leaf with leaflets arranged on each side of a common petiole or axis; also
applied to how the lateral veins are arranged in relation to the main vein. pinnatifid
pinnately lobed. pinnatisect
pinnately divided almost to midrib but segments still confluent. pinnule
ultimate free division (or leaflet) of a compound leaf, or a pinnate subdivision of a multipinnate
leaf. pistil
1. a single carpel when the carpels are free. 2. a group of carpels when the carpels are
united by the fusion of their walls. pistillate flower
a flower containing pistils but no stamens pistillode
A sterile or rudimentary pistil. pit
in tracheary elements, a section of the cell wall where the secondary wall is missing,
and the primary wall is present. Pits generally occur in pairs and link two cells. pith
the central region of a stem, inside the vascular cylinder; the spongy parenchymatous central
tissue in some stems and roots. placenta
the tissue within an ovary to which the ovules are attached. placentation
the arrangement of ovules inside ovary; for example axile, free-central, parietal, marginal,
basal, or apical. placodioid
The form of a lichen thallus which radiates outward with the ends of the radiating arms
peeling up from the substrate, but which lack a cortex on the underside (unlike foliose
lichens). Plant Breeders Rights (PBR)
these rights, governed by Plant Breeder’s Rights Acts give the plant breeder legal protection
over the propagation of a cultivar, and the exclusive rights to produce and to sell it,
including the right to license others to produce and sell plants and reproductive material
of a registered, deliberately bred variety. Cf. UPOV. Plant Variety Rights (PVR)
governed by the Plant Variety Rights the registration of new varieties is now governed by Plant
Breeders Rights. Plastochron
the time between successive leaf initiation events. plicate
pleated; folded back and forth longitudinally like a fan, such as the leaves of fan palm
species. The concept often appears in specific names in forms such as Kumara plicatilis and
Acacia plicata. Commonly such names are not correctly appropriate, but are applied to
distichous structures rather than plicate. -plinerved
(of leaves) a suffix indicating that the main nerves are lateral and arise from a point
distinctly above the base of the leaf. Combined with a numerical prefix to form words like
3-plinerved, 5-plinerved, and so on. Such leaves are especially characteristic of the
family Melastomataceae. plumose
like a feather; with fine hairs branching from a main axis. plumule
the part of an embryo that gives rise to the shoot system of a plant. Compare radicle. pluriflor
having many flowers per inflorescence. See also pauciflor and uniflor. pluriovulate
having many ovules as in placentae, carpels or ovaries. pneumatophore
a vertical, aerial (at low tide) appendage to the roots of some plants, through which
gases are exchanged, e.g. on mangroves. pod
1. a legume, the fruit of a leguminous plant, a dry fruit of a single carpel, splitting
along two sutures. 2. siliqua and silicula, the fruit of Brassicaceae,
a dry fruit composed of two carpels separated by a partition. pollen
powdery mass shed from anthers (of angiosperms) or microsporangia (of gymnosperms); the microspores
of seed plants; pollen-grains. pollen-mass
pollen-grains cohering by a waxy texture or fine threads into a single body; pollinium,
e.g. in orchids. pollen transmitting tissue
the tissue in the style of a flower through which the pollen tubes grow. pollination
the transfer of pollen from the male organ (anther) to the receptive region of a female
organ (stigma). pollinium
see pollen-mass. polygamodioecious
having bisexual and male flowers on some plants and bisexual and female flowers on others.
Compare androdioecious, andromonoecious, dioecious, monoecious, polygamomonoecious, polygamous. polygamomonoecious
having male, female and bisexual flowers on the same plant. Compare androdioecious, andromonoecious,
polygamodioecious, polygamous. polygamous
having bisexual and unisexual flowers on the same plant. polymorphic
of several different kinds (in respect to shape and/or size), hence polymorphism. See
also monomorphic (a single type) and dimorphic (two types) polyploid
with more than two of the basic sets of chromosomes in the nucleus; any sporophyte with cells
containing three or more complete sets of chromosomes. Various combinations of words
or numbers with ‘-ploid’ indicate the number of haploid sets of chromosomes, e.g. triploid
=3 sets, tetraploid=4 sets, pentaploid=5 sets, hexaploid=6 sets, and so on. polystemonous
having numerous stamens; the number of stamens being at least twice the number of sepals
or petals, but not strictly three or four times that number. pome
a fruit that has developed partly from the ovary wall but mostly from the hypanthium,
e.g. apple. population
1. all individuals of one or more species within a prescribed area.
2. a group of organisms of one species, occupying a defined area and usually isolated to some
degree from other similar groups. 3. in statistics, the whole group of items
or individuals under investigation. poricidal
opening by pores, like the capsule of a poppy, or like the anthers in several families of
plants. compare: longicidal posterior
positioned behind, towards the rear, proximal. Compare anterior, distal. prickle
adj. prickly A hard, pointed outgrowth from the surface of a plant (involving several
layers of cells but not containing a vein); a sharp outgrowth from the bark, detachable
without tearing wood. Compare thorn. primary species
In lichens, a species reproducing mainly by sexual reproduction, not vegetative reproduction. primary vein
The single vein or array of veins that is conspicuously larger than any others in a
leaf. In pinnate venation, the single primary vein can generally be found in the middle
of the leaf; in palmate venation, several such veins radiate from a point at or near
the base of the leaf. propagule
In lichens, a part of the thallus that has both fungal and algal parts and can break
off for vegetative reproduction, e.g. an isidium, phyllidium, phyllocladium, or soredium). prophyll
A leaf formed at the base of a shoot, usually smaller than those formed later. pro parte
In part; in nomenclature, used to denote that the preceding taxon includes more than one
currently recognized entity, and that only one of those entities is being considered. procumbent
Spreading along the ground but not rooting at the nodes; not as close to the ground as
prostrate. propagule
Any structure capable of generating a new plant; includes seeds, spores, bulbils, etc. prostrate
Lying flat on the ground. protandrous
Having male sex organs which mature before the female ones, e.g. a flower shedding pollen
before the stigma is receptive. Compare protogynous. proteranthous
new leaves appear before flowers. See also hysteranthous and synanthous prothallus
A #gametophyte plant, usually flattened and delicate, e.g. in ferns and fern allies. protogynous
Having female sex organs which mature before the male ones, e.g. a flower shedding pollen
after the stigma has ceased to be receptive. Compare protandrous. proximal
Near the point of origin or attachment. Compare distal. pruinose
Covered with a powdery, waxy material; having a bloom. pseudanthium
A type of inflorescence occurring in the Asteraceae and Euphorbiaceae, in which multiple flowers
are grouped together to form a flower-like structure, commonly called a head or capitulum. pseudo-
A prefix meaning “false, not genuine”, e.g. a pseudo-bulb is a thickened, bulb-like internode
in orchids, but not an actual bulb. pseudostipule
An enlarged, persistent axillary bud scale that resembles a stipule; common in Bignoniaceae. pseudoverticillate
Having the appearance of being whorled (verticillate), without actually being so. puberulous
Also puberulent. Covered with minute soft erect hairs.
pubescent Downy; covered with short, soft, erect hairs. pulverulent
Having powdery or crumbly particles as if pulverized. pulvinate
Having a pulvinus. pulvinus
a swelling at either end of a petiole of a leaf or petiolule of a leaflet, e.g. in Fabaceae,
that permits leaf movement. punctate
marked with dots. punctiform
Dot-like. pungent
Having a sharp, hard point. pustule
A blister-like swelling. pustulate
Having pustules. pyramidal
(of a growth habit) Tetrahedral; pyramid-shaped. pyrene
The stone of a drupe, consisting of the seed surrounded by the hardened endocarp. pyriform
Pear-shaped; a term for solid shapes that are broadest in the upper third and abruptly
narrowed near the base.==Q==
quadrate More or less square.==R==
raceme adj. racemose An indeterminate inflorescence
in which the main axis produces a series of flowers on lateral stalks, the oldest at the
base and the youngest at the top. Compare spike.
rachilla (rhachilla) the axis of a grass spikelet, above the glumes. rachis
(plural rachises; rachides) the axis of an inflorescence or a pinnate leaf; for example
ferns; secondary rachis is the axis of a pinna in a bipinnate leaf distal to and including
the lowermost pedicel attachment. radial
with structures radiating from a central point as spokes on a wheel, for example, the lateral
spines of a cactus. radiate
of daisies, of a capitulum, with ray florets surrounding disc florets. radical
springing from the root; clustered at base of stem. radicle
the part of an embryo giving rise to the root system of a plant. Compare plumule. rainforest
a moist temperate or tropical forest dominated by broad-leaved trees that form a continuous
canopy. ramet
an individual member of a clone. ramicaul
a single-leafed stem, as in Pleurothallis orchids. ray
1. zygomorphic (ligulate) flowers in a radiate flowerhead, that is, ray-florets/flowers,
for example Asteraceae. 2. each of the branches of an umbel. receptacle
the axis of a flower, in other words, floral axis; torus; for example in Asteraceae, the
floral base or receptacle is the expanded tip of the peduncle on which the flowers are
inserted. recurved
bent or curved backwards or downwards. reduplicate
folded outwards, or with the two abaxial surfaces together. reflexed
bent sharply back or down. registered name
a cultivar name accepted by the relevant International Cultivar Registration Authority. registration
1. the act of recording a new cultivar name with an International Cultivar Registration
Authority. 2. recording a new cultivar name with a statutory
authority like the Plant Breeder’s Rights Office.
3. recording a trademark with a trade marks office. regular
See actinomorphic. reniform
Kidney-shaped. resupinate
1. In botany, describing leaves or flowers that are in an inverted position because the
petiole or pedicel, respectively, is twisted 180 degrees. compare: #hyper-resupinate
2. In lichenology, referring to either having or being a fruiting body that lies flat on
the substrate, with the hymenium either over the whole surface or at the periphery. reticulate
forming a network (or reticulum), e.g. veins that join one another at more than one point. retrorse
Bent backwards or downwards. Compare antrorse. retuse
Having a blunt (obtuse) and slightly notched apex. revision
an account of a particular plant group, like an abbreviated or simplified monograph. Sometimes
confined to the plants of a particular region. Similar to a monograph in clearly distinguishing
the taxa and providing a means for their identification. Compare monograph. revolute
rolled under (downwards or backwards), for example when the edges of leaves are rolled
under towards the midrib. Compare involute. rhachis
see rachis. rhizine
The “root” or “trunk” projection of a foliose lichen that attaches the lichen to the substrate
(what the lichen is growing on) rhizodermis
the root epidermis, the outermost primary cell layer of the root rhizome
a perennial underground stem usually growing horizontally. See also stolon. Abbreviation:
rhiz. rhizosphere
the below-ground surface of plants and adjacent soil as a habitat for microorganisms. rhombic
like a rhombus: an oblique figure with four equal sides. Compare trapeziform, trullate. rhomboid
a four-sided figure with opposite sides parallel but with adjacent sides an unequal length
(like an oblique rectangle); see also rhombic. rhomboidal
a shape, for instance of a leaf, that is roughly diamond-shaped with length equal to width. rimose
with many cracks, as in the surface of a crustose areolate lichen. root
a unit of a plant’s axial system which is usually underground, does not bear leaves,
tends to grow downwards, and is typically derived from the radicle of the embryo. root hairs
outgrowths of the outermost layer of cells just behind the root tips, functioning as
water-absorbing organs. root microbiome
the dynamic community of microorganisms associated with plant roots. rootstock
1. the part of a budded or grafted plant which supplies the root system, also simply called
a stock. 2. plants selected to produce a root system
with some specific attribute, e.g. a virus-free rootstock. rosette
when parts are not whorled or opposite but appear so, due to the contractions of internodes,
e.g. the petals in a double rose or a basal cluster of leaves (usually close to the ground)
in some plants. rostrate
with a beak. rotate
circular and flattened; for example a corolla with a very short tube and spreading lobes
(for instance some Solanaceae). ruderal
a plant that colonises or occupies disturbed waste ground. See also weed. rudimentary
poorly developed and not functional. Compare vestigial. rugose
Wrinkled. rugulose
Finely wrinkled. ruminate
(usually applied to endosperm) Irregularly grooved or ridged; appearing chewed, e.g.
the endosperm in certain members of Myristicaceae. runcinate
Sharply pinnatifid or cleft, with the segments directed downward. runner
See stolon. rupicolous
Rupestral, saxicolous, growing on or among rocks. Compare epilithic and lithophytic. rush
A plant belonging to the family Juncaceae or, more loosely, applied to various monocotyledons.==S==
saccate Pouched or shaped like a sack. sagittate
Shaped like the head of an arrow; narrow and pointed but gradually enlarged at the base
into two straight lobes directed downwards; may refer only to the base of a leaf with
such lobes. Compare hastate. salverform
Trumpet-shaped; having a long, slender tube and a flat, abruptly expanded limb. samara
A dry, indehiscent fruit with its wall expanded into a wing, e.g. in the genus Acer. samphire
A common name given to various edible coastal plants, such as Salicornia spp. (Amaranthaceae),
Crithmum maritimum (Apiaceae) and Limbarda crithmoides (Asteraceae). saprophyte
adj. saprophytic An organism deriving its nourishment from decaying organic matter and
usually lacking chlorophyll. Compare parasite and epiphyte.
sarmentose Having long, slender, prostrate stolons (runners). saxicolous
growing on stone, like some lichens. scabrid
Also scabrous. Rough to the touch, with short hard protrusions or hairs.
scalariform Ladder-like in structure or appearance. scale
1. A reduced or rudimentary leaf, for example around a dormant bud.
2. A flattened epidermal outgrowth, such as those commonly found on the leaves and rhizomes
of ferns. scandent
climbing, by whatever means. See also: scandent in Wiktionary. scape
adj. scapose A stem-like flowering stalk of a plant with radical leaves.
scapose Having the floral axis more or less erect
with few or no leaves; consisting of a scape. scarious
dry and membranous. schizocarp
a dry fruit formed from more than one carpel but breaking apart into individual carpels
(mericarps) when ripe. scion
The aerial part of a graft combination, induced by various means to unite with a compatible
understock or rootstock. sclereid
A cell with a thick, often lignified, cell wall that is shorter than a fiber cell and
dies soon after the thickening of its cell wall. sclerenchyma
A strengthening or supporting tissue composed of sclereids or of a mixture of sclereids
and fibers. sclerophyll
adj. sclerophyllous A plant with hard, stiff leaves; leaves stiffened with thick-walled
cells. scorpioid
(of a cymose inflorescence) Branching alternately on one side and then the other. Compare helicoid. scrobiculate
Having very small pits. scrubland
Dense vegetation dominated by shrubs. scurf
Minute, loose, membranous scales on the surface of some plant parts, such as leaves. secondary metabolite
Chemicals produced by a plant that do not have a role in so-called primary functions
such as growth, development, photosynthesis, reproduction, etc. secondary species
In lichens, a “species” taxon of lichen reproducing only by vegetative means, whose components
reproduce mainly by sexual means – cf. primary species. secretory tissue
The tissues concerned with the secretion of gums, resins, oils and other substances in
plants. section (sectio)
The category of supplementary taxa intermediate in rank between subgenus and series. It is
a singular noun always written with a capital initial letter, in combination with the generic
name. secund
Having all the parts grouped on one side or turned to one side (applied especially to
inflorescences). sedge
A plant belonging to the family Cyperaceae. seed
A ripened ovule, consisting of a protective coat enclosing an embryo and food reserves;
a propagating organ formed in the sexual reproductive cycle of gymnosperms and angiosperms (together,
the seed plants). segment
A part or subdivision of an organ, e.g. a petal is a segment of the corolla. A term
sometimes used when the sepals and petals are indistinguishable. self-pollination
(also selfing) The acceptance by stigmas of pollen from the same flower or from flowers
on the same plant, which means they are self-compatible. semaphyll
A structure such as a bract or a sepal (if the remainder of the perianth is inconspicuous)
which has become modified to attract pollinators. Plural: semaphylls semelparity
When a plant flowers once then dies. semiterete
Rounded on one side but flat on the other. See also terete. senecioid
See anthemoid. sensitive
A descriptive term for stigmas that, in response to touch, close the two lobes of the stigma
together, ending the receptivity of the stigma, at least for the time that the lobes are closed
together. Mimulus is perhaps the best-known example. sensu
In the sense of. sensu auct.
(of a plant group or name) As cited by a named authority. sensu amplo
(of a plant group or name) In a generous or ample sense. sensu lato
(of a plant group) In a broad sense. sensu strictissimo
(of a plant group) In the narrowest sense. sensu stricto
(of a plant group) In a narrow sense. sepal
In a flower, one of the segments or divisions of the outer whorl of non-fertile parts surrounding
the fertile organs; usually green. Compare petal. septicidal
(of a fruit) Dehiscing along the partitions between loculi. Compare loculicidal. septum
pl. septa A partition, e.g. the membranous wall separating the two valves of the pod
of Brassicaceae. seriate
Arranged in rows. sericeous
Silky with dense appressed hairs. series
The category of supplementary taxa intermediate in rank between section and species. It is
often used as a plural adjective, as in “Primula subgenus Primula sect. Primula series Acaules”. serrate
Toothed with asymmetrical teeth pointing forward; like the cutting edge of a saw. serrulate
Finely serrate. sessile
Attached without a stalk, e.g. of a leaf without a petiole or a stigma, when the style is absent. seta
pl. setae; adj. setose, setaceous A bristle or stiff hair (in Bryophytes, the stalk of
the sporophyte). A terminal seta is an appendage to the tip of an organ, e.g. the primary rachis
of a bipinnate leaf in Acacia. sheath
A tubular or rolled part of an organ, e.g. the lower part of the leaf in most grasses. shoot
The aerial part of a plant; a stem including its dependent parts (leaves, flowers, etc.). shrub
A woody perennial plant without a single main trunk, branching freely, and smaller than
a tree. sigmoid
Shaped like the letter ‘S’. silicula
a stout siliqua (not more than twice as long as wide). siliqua
a dry, dehiscent fruit (more than twice as long as wide) formed from a superior ovary
of two carpels, with two parietal placentas and divided into two loculi by a ‘false’ septum. silky
Densely covered with fine, soft, straight, appressed hairs, with a lustrous sheen and
satiny to the touch. silviculture
The science of forestry and the cultivation of woodlands for commercial purposes and wildlife
conservation. simple
Undivided or unsegmented, e.g. a leaf not divided into leaflets (note, however, that
a simple leaf may still be entire, toothed or lobed) or an unbranched hair or inflorescence. sinuate
Having deep, wave-like depressions along the margins, but more or less flat. Compare undulate. sinus
A notch or depression between two lobes or teeth in the margin of an organ. solitary
Single, of flowers that grow one plant per year, one in each axil, or widely separated
on the plant; not grouped in an inflorescence. soralia
In a lichen, the structure that bears soredium for non sexual reproduction. soredium
pl. soredia In a lichen, a small groups of algal cells surrounded by fungal filaments
that form in soralia, which break off and grow new lichens without sexual reproduction
after being dispersed by wind. Compare to an isidium, which breaks off and is dispersed
by mechanical means. sp.
An abbreviation of species (singular), often used when the genus is known but the species
has not been determined, as in “Brassica sp.” See spp. spp.
An abbreviation of species (plural), often used to collectively refer to more than one
species of the same genus, as in “Astragalus spp.” See sp. spadix
A spicate (spike-like) inflorescence with a stout, often succulent axis. spathe
adj. spathaceous A large bract ensheathing an inflorescence. Traditionally any broad
flat blade. spathulate (spatulate)
Spoon-shaped; broad at the tip with a narrowed projection extending to the base. species
A group, or populations of individuals, sharing common features and/or ancestry, generally
the smallest group that can be readily and consistently recognized; often, a group of
individuals capable of interbreeding and producing fertile offspring. The basic unit of classification,
the category of taxa of the lowest principal rank in the nomenclatural hierarchy. specific epithet
Follows the name of the genus, and is the second word of a botanical binomial. The generic
name and specific epithet together constitute the name of a species; i.e. the specific epithet
is not the species name. spica
adj. spicate A spike. spike
adj. spicate An unbranched, indeterminate inflorescence in which the flowers are without
stalks. Compare raceme. spikelet
A subunit of a spike inflorescence, especially in grasses, sedges and some other monocotyledons,
consisting of one to many flowers and associated bracts or glumes. spine
adj. spinose A stiff, sharp structure formed by the modification of a plant organ that
contains vascular tissue, e.g. a lateral branch or a stipule; includes thorns.
spinescent Ending in a spine; modified to form a spine. spiral
Of arrangement, when plant parts are arranged in a succession of curves like the thread
of a screw, or coiled in a cylindrical or conical manner. splash-cup (sporangia)
A cup-like structure in cryptogams functioning in spore dispersal, whereby the energy of
raindrops falling into the cup causes the water to splash back out carrying the spore. sporangium (sporangia)
A structure in which spores are formed. sporangiophore
An organ bearing sporangia, e.g. the cones of Equisetum. spore
A haploid propagule, produced by meiosis in diploid cells of a sporophyte that can germinate
to produce a multicellular gametophyte. sporocarp
A fruiting body containing spores. sporophyll
In pteridophytes, a modified leaf that bears a sporangium or sporangia. sporophyte
The haploid multicellular phase in the alternation of generations of plants and algae that produces
the spores. Compare gametophyte. sport
A naturally occurring variant of a species, not usually present in a population or group
of plants; a plant that has spontaneously mutated so that it differs from its parent
plant. spreading
Extending horizontally, e.g. in branches. Standing out at right angles to an axis, e.g.
in leaves or hairs. spur
1. a short shoot. 2. a conical or tubular outgrowth from the
base of a perianth segment, often containing nectar. squamule
(plural squamules, squamulae) small scales; In lichens, squamules are overlapping plate-like
forms, sometimes overlapping so much as to become leaf-like, but which lack a lower cortex,
unlike the leafy forms of foliose lichens – adjective: squamulose squamulose
Covered with small scales (squamules). In lichens, being composed of squamules. squarrose
Having tips of leaves, stems, etc. radiating or projecting outwards, e.g. in the moss Rhytidiadelphus
squarrosus. s.t.
An abbreviation for “sometimes”. Compare usu. and oft. stalk
The supporting structure of an organ, usually narrower in diameter than the organ itself. stamen
adj. staminate The male organ of a flower, consisting (usually) of a stalk called the
filament and a pollen-bearing head called the anther.
staminate flower A flower with stamens but no pistil staminode
A sterile stamen, often rudimentary, sometimes petal-like. standard
The large posterior petal of pea-flowers. standard specimen
A representative specimen of a cultivar or other taxon which demonstrates how the name
of that taxon should be used. stele
The primary vascular system (phloem, xylem and ground tissue) of plant stems and roots. stellate
Star-shaped. stem
The plant axis, either aerial or subterranean, which bears nodes, leaves, branches and flowers. stem-clasping
See amplexicaul. stenospermocarpy
The development or production of fruit that is seedless or has minute seeds because of
the abortion of seed development. Compare parthenocarpy. sterile
Infertile, as with a stamen that does not bear pollen or a flower that does not bear
seed. stigma
The pollen-receptive surface of a carpel or group of fused carpels, usually sticky; usually
a point or small head at the summit of the style. stipe
(in ferns) The stalk of a frond; generally a small stalk. stipella
Also stipel; pl. stipellae One of two small secondary stipules at the base of leaflets
in some species. stipitate
stalked; borne on a stipe; of an ovary, borne on a gynophore. stipulate
Bearing stipules. stipule
A small appendage at the bases of leaves in many dicotyledons. stock
See rootstock. stolon
Also runner. A slender, prostrate or trailing stem, producing roots and sometimes erect
shoots at its nodes. See also rhizome. stoloniferous
Having stolons. stoma
pl. stomata A pore or small hole in the surface of a leaf (or other aerial organ) allowing
the exchange of gases between tissues and the atmosphere.
striate Striped with parallel, longitudinal lines
or ridges. strigose
Covered with appressed, straight, rigid, bristle-like hairs; the appressed equivalent of hispid. strobilus
pl. strobili A cone-like structure consisting of sporophylls (e.g. conifers and club mosses)
or sporangiophores (e.g. in Equisetopsida) borne close together on an axis.
style An elongated part of a carpel or a group of
fused carpels between the ovary and the stigma. stylodium
An elongate stigma that resembles a style; a false style, e.g. commonly found in the
Poaceae and Asteraceae. stylopodium
A swelling on top of the ovary, at the base of the styles commonly found in flowers of
the Apiaceae stylulus
the elongated apex of a free carpel which functions like the style of a syncarpous ovary,
allowing pollen tubes from its stigma to enter the locule of only that carpel. subcoriaceous
Slightly leathery or coriaceous. subgenus
A category of supplementary taxa intermediate between genus and section. The name of a subgenus
is a singular noun, always has a capital initial letter and is used in combination with the
generic name, e.g. Primula subgenus Primula. subglobose
Inflated, but less than spherical. See also globose. subshrub
Also called an undershrub. A small shrub which may have partially herbaceous stems, but generally
a woody plant less than 1 metre (3.3 ft) high. subspecies
A taxonomic category within a species, usually used for geographically isolated or morphologically
distinct populations of the same species. Its taxonomic rank occurs between species
and variety. subtend
To stand beneath or close to, as in a bract at the base of a flower. subquadrangular
Not quite square. Compare quadrangular. subulate
Narrow and tapering gradually to a fine point. succulent
1. Juicy or fleshy. 2. A plant with a fleshy habit. sucker
A shoot of more or less subterranean origin; an erect shoot originating from a bud on a
root or a rhizome, sometimes at some distance from the stem of the plant. suffrutex
pl. suffrutices A subshrub or undershrub. sulcate
Furrowed; grooved. May be single (monosulcate), two (bisulcate) or many (polysulcate). superficial
On the surface. superior
Of an ovary, borne above the level of attachment of the other floral parts, or above the base
of a hypanthium. Compare inferior and half-inferior. suspended
Of an ovule, when attached slightly below the summit of the ovary. Compare pendulous. suture
A junction or seam of union. See fissure and commissure. sward
Extensive, more or less even cover of a surface, e.g. a lawn grass. Compare tussock. sympatric
Having more or less similar or overlapping ranges of distribution. sympodial
A mode of growth in which the main axis is repeatedly terminated and replaced with a
lateral branch. Examples occur in the family Combretaceae, including the genera Terminalia
and Combretum. syconium
A hollow infructescence containing multiple fruit, such as that of a fig. syn-
Also sym-. A prefix meaning “with, together”. symmetrical
Capable of being divided into at least two equal, mirror-image halves (e.g. zygomorphic)
or having rotational symmetry (e.g. regular or actinomorphic). Compare irregular and asymmetrical. sympetalous
Having united (connate or fused) petals. See also syntepalous (having fused tepals). synangium
A fused aggregate of sporangia, e.g. in the trilocular sporangia of the whisk fern Psilotum. synanthous
A type of growth in which new leaves and flowers appear and die back at the same time. See
also hysteranthous and proteranthous. synaptospermy
The dispersal of diaspores as units, where each bears more than one seed, for example
where each diaspore comprises an entire inflorescence, as in Brunsvigia or multi-seeded fruit as
in Tribulus zeyheri. Ephemeral synaptospermy is the term for when the diaspores split into
units containing fewer or single seeds each, as in most tumbleweeds. True synaptospermy
is when the diaspore generally remains entire until germination, as commonly happens in
species of Grielum. syncarpous
(of a gynoecium) Composed of united carpels. synonym
An outdated or ‘alternative’ name for the same taxon. synoecious
A synonym of bisexual. syntepalous
Having fused tepals. See also sympetalous (having fused petals).==T==
taproot The primary descending root of a plant with
a single dominant root axis. tartareous
Having a surface that is course, thick, rough, and crumbling. taxon
pl. taxa A group or category in a system of classification.
taxonomy The study of the principles and practice of
classification. tegmen
The inner layer of the testa (seed coat). It develops from the inner integument of the
ovule. tendril
A slender organ modified from a stem, leaf, leaflet or stipule and used by climbing plants
to cling to an object. tepal
A perianth segment, either sepal or petal; usually used when all perianth segments are
indistinguishable in appearance. terete
Also semiterete. Circular in cross-section; more or less cylindrical without grooves or
ridges. terminal
Situated at the tip or apex. ternate
In groups of three; of leaves, arranged in whorls of three; of a single leaf, having
the leaflets arranged in groups of three. terrestrial
Of or on the ground; of a habitat, on land as opposed to in water (aquatic), on rocks
(lithophytic), or on other plants (epiphytic). testa
The seed coat. tetrad
A group of four; usually used to refer to four pollen grains which remain fused together
through maturity (e.g. in the Epacridaceae). tetragonal
Square; having four corners; four-angled, e.g. the cross-sections of stems of herbaceous
Lamiaceae. tetramerous
In four parts, particularly with respect to flowers; four parts in each whorl. See also
trimerous and pentamerous. tetraploid
Having four complete sets of chromosomes in each sporophyte cell. tetraspore
The asexual spore of red algae. It is so named because each sporangium produces just four
spores. See Rhodophyceae. thalamus
Obsolete. 1. A synonym for receptacle. 2. The inflorescence disk of members of the
Asteraceae. 3. A calyx, as used by Carl Linnaeus. thallus
The “vegetative” part (part other than sexual fruitbodies) of a lichen that has both the
fungus (mycobiont) and photobiont; plural thalli theca
One of the usually two synangia in which pollen is produced in flowering plants. It consists
of two fused sporangia known as pollen sacs. The wall between the pollen sacs disintegrates
before dehiscence, which is usually by a common slit. thorn
A sharp, stiff point, usually a modified stem, that cannot be detached without tearing the
subtending tissue; a spine. Compare prickle. throat
The opening of a corolla or perianth. thyrse
A branched inflorescence in which the main axis is indeterminate (racemose) and the lateral
branches determinate (cymose). tomentum
A dense covering of short, matted hairs. Tomentose is often used as a general term for bearing
an indumentum, but this is not a recommended use. toothed
Having a more or less regularly incised margin. torus
See receptacle. transmitting tissue
See pollen transmitting tissue. trapeziform
1. Like a trapezium (a four-sided figure with two parallel sides of unequal length).
2. Like a trapezoid (a four-sided figure, or quadrilateral, with neither pair of sides
equal); sometimes used erroneously as a synonym for rhombic. tree
A woody plant, usually with a single distinct trunk and generally more than 2–3 metres
(6.6–9.8 ft) tall. triad
A group of three. triangular
Planar and with 3 sides. tribe
A taxonomic grouping that ranks between genus and family. trichome
In non-filamentous plants, any hair-like outgrowth from the epidermis, e.g. a hair or bristle;
sometimes restricted to unbranched epidermal outgrowths. trifid
Split into three parts. See also bifid. trifoliate
A compound leaf of three leaflets; for example, a clover leaf. trifoliolate
See trifoliate. trigonous
Triangular in cross-section and obtusely angled. Compare triquetrous. trimerous
In three parts, particularly with respect to flowers; having three parts in each whorl.
See also tetramerous and pentamerous. trinerved
Having three nerves or veins. triplinerved
(of leaves) Having three main nerves with the lateral nerves arising from the midnerve
above the base of the leaf. triquetrous
More or less triangular in cross-section, but acutely angled (with 3 distinct longitudinal
ridges). Compare trigonous. trivalve
Divided into three valves. Also trivalvar. See also bivalve. trivial name
The second word in the two-part scientific name of an organism. Compare specific epithet. trophophyll
A vegetative, nutrient-producing leaf or microphyll whose primary function is photosynthesis.
It is not specialized or modified for some other function. Compare sporophyll. trullate
Ovate but angled, as with a bricklayer’s trowel; inversely kite-shaped. Compare rhombic. truncate
Cut off squarely; having an abruptly transverse end. trunk
The upright, large and typically woody main stem of a tree. truss
A compact cluster of flowers or fruits arising from one centre; evident in many rhododendrons. tuber
An underground storage organ formed by the swelling of an underground stem which produces
buds and stores food, forming a seasonal perennating organ, e.g. a potato. Compare tuberoid. tubercle
A small wart-like outgrowth or protuberance of tissue. tuberculate
Covered in tubercles. See warty. tuberoid
An underground storage organ formed by the swelling of a root; occurs in many orchids. tuberous
Resembling a tuber or producing tubers. tubular
Having the form of a tube or cylinder. tufted
Densely fasciculate at the tip. tunic
The outer covering of some bulbs and corms. tunicate
(of bulbs) Consisting of concentric coats. turbinate
Shaped like a spinning top. turgid
Swollen with liquid; bloated; firm. Compare flaccid. tussock
A dense tuft of vegetation, usually well separated from neighbouring tussocks, for example in
some grasses. Compare sward. two-ranked
Having leaves arranged in two rows in the same plane, on opposite sides of the branch.
See distichous. type
An item (usually an herbarium specimen) to which the name of a taxon is permanently attached,
i.e. a designated representative of a plant name. Important in determining the priority
of names available for a particular taxon. type genus
In nomenclature, a single genus on which a taxonomic family is based.==U==
umbel A racemose inflorescence in which all the
individual flower stalks arise in a cluster at the top of the peduncle and are of about
equal length; in a simple umbel, each stalk is unbranched and bears only one flower. A
cymose umbel looks similar to an ordinary umbel but its flowers open centrifugally. umbo
A rounded elevation, such as in the middle of the top of an umbrella or mushroom; a central
boss or protuberance, such as on the scale of a cone. umbonate
Having an umbo, with a conical or blunt projection arising from a flatter surface, as on the
top of a mushroom or in the scale of a pine cone. unciform
Hook-shaped. uncinate
Having a hook at the apex. undershrub
A low shrub, often with flowering branches that die off in winter. Compare subshrub. understory
Plant life growing beneath the forest canopy. undulate
Wavy and not flat. Compare sinuate. uniflor
Having a single flower (uniflory). Compare pauciflor (few) and pluriflor (many). unilocular
Having one loculus or chamber, e.g. the ovary in the families Proteaceae and Fabaceae. uniserial
Arranged in a single row or series. Unbranched. Uniseriate. uniseriate
Arranged in a single row or series. Unbranched. Uniserial. unisexual
Of one sex; bearing only male or only female reproductive organs, dioecious, dioicous.
See Sexual reproduction in plants. unitegmic
(of an ovule) Covered by a single integument. urceolate
Shaped like an urn or pitcher, with a swollen middle and narrowing top. Examples include
the pitchers of many species of the pitcher plant genera Sarracenia and Nepenthes. usu.
An abbreviation for usually. Compare s.t. and oft. utricle
1. A small bladder; a membranous bladder-like sac from the ovary wall, thin pericarp, becomes
more or less bladdery or inflated at maturity enclosing an ovary or fruit.
2. In sedges, a fruit in which the fruit is loosely encloses from a modified tubular bract,
see perigynium.==V==
vallecular canal A resin canal coinciding with a longitudinal
groove in the seeds of Asteraceae. A longitudinal cavity in the cortex of the stems of Equisetum,
coinciding with a groove in the stem surface. valvate
(of sepals and petals in bud) Meeting edge-to-edge but not overlapping. valve
A portion of an organ that fragments or splits open, e.g. the teeth-like portions of a pericarp
in a split (dehisced) capsule or pod when ripe. var.
An abbreviation of varietas. variant
A plant or group of plants showing some measure of difference from the characteristics associated
with a particular taxon. variegated
Irregularly marked with blotches or patches of another colour. varietas
Often variety in common usage and abbreviated as var. A taxonomic rank below that of species
and between the ranks of subspecies and form. vascular
Referring to the conducting tissues (xylem and phloem) of vascular plants. vascular bundle
A bundle of vascular tissue in the primary stems of vascular plants, consisting of specialised
conducting cells for the transport of water (xylem) and assimilate (phloem). vasculum
A container used by botanists for collecting field specimens. vein
A strand of vascular tissue, e.g. in the leaves of vascular plants; a nerve. veinlet
A small vein; the ultimate (visible) division of a vein. velamen
A spongy tissue covering the aerial roots of orchids and some other epiphytes. velvety
Densely covered with fine, short, soft, erect hairs. venation
The arrangement of veins in a leaf. ventral
The front; in particular, towards the axis (adaxial) in a lateral organ or towards the
substrate in a prostrate plant. Compare dorsal and abaxial. vernation
The arrangement of unexpanded leaves in a bud; the order in which leaves unfold from
a bud. vernonioid
In Compositae, style with sweeping hairs borne on abaxial surfaces of style branches. verruciform
Wart-like in form. verrucose
Having warts. verruculose
Minutely verrucose; minutely warty. versatile
(of anthers) Swinging freely about the point of attachment to the filament. verticillate
Arranged in one or more whorls, i.e. several similar parts arranged at the same point of
the axis, e.g. leaf arrangement. Compare pseudoverticillate (appearing whorled or verticillate but not
actually so). verticillaster
A type of pseudoverticillate inflorescence, typical of the Lamiaceae, in which pseudo-whorls
are formed from pairs of opposite cymes. vesicular
(of hairs) Bladder-like; vesciculous, bearing such hairs. vessel
A capillary tube formed from a series of open-ended cells in the water-conducting tissue of a
plant. vestigial
Reduced in form and function from the normal or ancestral condition. villous
Abounding in or covered with long, soft, straight hairs; shaggy with soft hairs. vine
1. Scandent plants climbing by means of trailing or twining stems or runners.
2. Such a stem or runner. 3. A member of the genus Vitis. virgate
diminutive: virgulate Wand-shaped, twiggy, especially referring to erect, straight stems.
In mycology, referring to a pileus with radiating ribs or lines.
Viridiplantae A clade of autotrophic organisms that includes
the green algae, Charophyta and land plants, all of which have cellulose in their cell
walls, chloroplasts derived from primary endosymbiosis with Cyanobacteria that contain chlorophylls
a and b and lack phycobilins. viscid
Sticky; coated with a thick, syrupy secretion. viviparous
1. Referring to seeds or fruits which germinate before being shed from the parent plant.
2. The development of plantlets on non-floral organs, e.g. leaves.==W==warty
A surface covered with small round protuberances, especially in fruit, leaves, twigs and bark.
See tuberculate. watershoot
An erect, strong-growing or epicormic shoot developing from near the base of a shrub or
tree, but distinct from a sucker. weed
1. Any plant growing where it is not wanted; commonly associated with disrupted habitats.
See also ruderal. 2. (agricultural weed) An unwanted plant which
grows among agricultural crops. 3. (environmental weed) A naturalised, exotic
or ecologically ‘out-of-balance’ indigenous species outside the agricultural or garden
context which, as a result of invasion, adversely affects the survival or regeneration of indigenous
species in natural or partly natural vegetation communities. wild
Originating from a known wild or purely natural habitat (wilderness). whorl
A ring of organs borne at the same level on an axis, for example leaves, bracts or floral
parts. wing
1. A membranous expansion of a fruit or seed which aids in dispersal, for instance on pine
seeds. 2. A thin flange of tissue extending beyond
the normal outline of a structure, e.g. on the column of some orchids, on stems, on petioles.
3. One of the two lateral petals of a flower of subfamily Faboideae of family Fabaceae,
located between the adaxial standard (banner) petal and the two abaxial keel petals. woolly
Very densely covered with long, more or less matted or intertwined hairs, resembling a
sheep’s wool.==X==
xeromorph A plant with structural features (e.g. hard
or succulent leaves) or functional adaptations that prevent water loss by evaporation; usually
associated with arid habitats, but not necessarily drought-tolerant. Compare xerophyte. xerophyte
A plant generally living in a dry habitat, typically showing xeromorphic or succulent
adaptation; a plant able to tolerate long periods of drought. Compare xeromorph. xylem
A specialised water-conducting tissue in vascular plants.==Z==
zonate having light and dark circular bands or rings. zygomorphic
bilaterally symmetrical; symmetrical about one vertical plane only; applies to flowers
in which the perianth segments within each whorl vary in size and shape. Compare actinomorphic,
irregular. zygote
a fertilized cell, the product of fusion of two gametes.==See also==
Glossary of plant morphology International scientific vocabulary
Leaf shape Plant morphology
Floral formula – abbreviations used in describing flower parts
Glossary of biology Glossary of scientific naming
Plant anatomy Palynology

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