Glossary of botanical terms

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This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary of leaf morphology. For other related terms, see Glossary of phytopathology and List of Latin and Greek words commonly used in systematic names.

Contents

A

In the bud Tetradenia riparia leaves had their upper surfaces turned toward the stem and the axil. The lower surface is abaxial ("away from the axis"), and the upper surface is adaxial. Tetradenia riparia leaves and buds IMG 2103c.jpg
In the bud Tetradenia riparia leaves had their upper surfaces turned toward the stem and the axil . The lower surface is abaxial ("away from the axis"), and the upper surface is adaxial.
Viburnum abscission Viburnum abscission.jpg
Welwitschia mirabilis presents an example of an acaulescent growth habit unusual in so large a plant species. Welwitschia at Ugab River basin.jpg
Welwitschia mirabilis presents an example of an acaulescent growth habit unusual in so large a plant species.
Schematic diagrams of the accumbent arrangement of the cotyledons and radicle in a seed of Erysimum Accumbent cotyledon.jpg
Schematic diagrams of the accumbent arrangement of the cotyledons and radicle in a seed of Erysimum
Achenes on the surface of the stem of the infructescence of a strawberry Strawberry.achene.es.jpg
Achenes on the surface of the stem of the infructescence of a strawberry
Geranium incanum flowers are actinomorphic, having five axes of symmetry, as opposed to the two axes of symmetry of the zygomorphic flowers of most species of the related genus Pelargonium. Geranium incanum floral stages IMG 2752.jpg
Geranium incanum flowers are actinomorphic , having five axes of symmetry, as opposed to the two axes of symmetry of the zygomorphic flowers of most species of the related genus Pelargonium .
Fern frond with acuminate leaflets Ferns- British and exotic.. (1856) (14595221459).jpg
Fern frond with acuminate leaflets
Adelphous stamens in flower of Gossypium tomentosum Starr-091104-0742-Gossypium tomentosum-flower-Kahanu Gardens NTBG Kaeleku Hana-Maui (24961202116).jpg
Adelphous stamens in flower of Gossypium tomentosum
Watsonia flower slit open and with one stamen bent upward to show its adnate attachment to the petal. Watsonia flower with adnate stamens and connate petals IMG 1974c.jpg
Watsonia flower slit open and with one stamen bent upward to show its adnate attachment to the petal.
Diagram of a coconut fruit. The albumen (endosperm) is labelled Alb. Contributions from the New York Botanical Garden (1899-) (20677430362).jpg
Diagram of a coconut fruit. The albumen (endosperm) is labelled Alb.
Caffeine is an alkaloid with four nitrogen atoms in its carbon skeleton. Caffeine.png
Caffeine is an alkaloid with four nitrogen atoms in its carbon skeleton.
Rothmannia leaf with extensively anastomose venation Rothmannia globosa, blaarbearing, Uniegeboutuine, a.jpg
Rothmannia leaf with extensively anastomose venation
Androgynous flower of Sandersonia aurantiaca cut open longitudinally to show the androecium, which comprises the anthers surrounding the green central pistil. Sandersonia aurantiaca 1DS-II 2-5399.jpg
Androgynous flower of Sandersonia aurantiaca cut open longitudinally to show the androecium , which comprises the anthers surrounding the green central pistil.
Anther of Lilium in a state of anthesis, dehiscent and releasing pollen 2012-01-04 17-57-36-lys.jpg
Anther of Lilium in a state of anthesis, dehiscent and releasing pollen
A Neea species, family Nyctaginaceae, presents an example of an anthocarp: the calyx and style remain around the ripening fruit. Neea sp., Nyctaginaceae, Atlantic forest, northeastern Bahia, Brazil (9463277249).jpg
A Neea species, family Nyctaginaceae, presents an example of an anthocarp : the calyx and style remain around the ripening fruit.
Aphananthous flowers of oaks such as Quercus robur, being anemophilous, have no need of being conspicuous to pollinating animals. Quercus robur RF.jpg
Aphananthous flowers of oaks such as Quercus robur , being anemophilous, have no need of being conspicuous to pollinating animals.
Apical bud of a poplar shoot Populus angustifolia x balsamifera (5001208139).jpg
Apical bud of a poplar shoot
The apparently separate nuts of Ochrosia borbonica actually are apocarpous carpels, two from each flower. Ochrosia borbonica fruit 1.JPG
The apparently separate nuts of Ochrosia borbonica actually are apocarpous carpels, two from each flower.
Apophyses on the tips of the cone scales of Araucaria cunninghamii amount to spikes. Starr 070404-6665 Araucaria cunninghamii.jpg
Apophyses on the tips of the cone scales of Araucaria cunninghamii amount to spikes.
Hairs on the leaves of Alyssum linifolium are stellate and appressed to the leaf surface. Alyssum linifolium leaf2 ST (14931806424).jpg
Hairs on the leaves of Alyssum linifolium are stellate and appressed to the leaf surface.
Arachnoid leaves of unidentified Gazania Arachnoid leaves of unidentified Gazania 2012 07 05 7252s.JPG
Arachnoid leaves of unidentified Gazania
Spines of cactus Gymnocalycium bayrianum emerging from the areoles on the stem nodes Gymnocalycium bayrianum GN88 69 spines.JPG
Spines of cactus Gymnocalycium bayrianum emerging from the areoles on the stem nodes
Blighia, Akee seeds, one whole, one in longitudinal section, showing the pale aril 2013.11-411-169 Akee,seed&aril(whole,LS) Bobo-Dioulasso,BF thu14nov2013-0953h.jpg
Blighia, Akee seeds, one whole, one in longitudinal section, showing the pale aril
Infructescence of wild rye, showing prominent awns Wild rye.jpg
Infructescence of wild rye, showing prominent awn s
Anatomy of an awn and bristles on a species of Australian grass Rytidosperma longifolium33 floret19 (9412598806).jpg
Anatomy of an awn and bristles on a species of Australian grass
Axillary buds in leaf Searsia angustifolia (Rhus angustifolia) axillary and apical buds 5471.jpg
Axillary buds in leaf
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. [1] Contrast adaxial .
abort
To abandon development of a structure or organ.
abscission
The shedding of an organ that is mature or aged, as of 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. Such tissue is 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. [1] Examples include some species of Agave , Oxalis , and Attalea . [2] Antonym of caulescent (possessing stem)
accrescent
Increasing in size with age, such as a calyx that continues to grow after the corolla has fallen, [1] e.g. in Physalis peruviana .
accumbent
Lying against another part of the plant; when applied to a cotyledon, it means that one edge of the cotyledon lies along the radicle.
-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, of which the type genus is Rosa .
achene
A dry, one-seeded indehiscent fruit [3] in which the true fruit is not the so-called "berry", but the achenes, which are the so-called "seeds" on the infructescence, e.g. in the genus Fragaria .
acicular
Slender or needle-shaped. [3]
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, as opposed 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 reaching the margin in most species, but not all.
actinomorphic
Regular or radially symmetrical; [4] 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 asymmetrical , irregular , and zygomorphic .
aculeate
Armed with prickles, [5] e.g. the stem of a rose.
acuminate
Tapering gradually to a point, with concave sides approaching the point. [5] Contrast acute and mucronate .
acute
1.  Sharply pointed, but not drawn out, with straight sides approaching the point. [5] Contrast acuminate .
2.  Converging at an angle of less than 90°. Contrast obtuse .
ad-
A prefix meaning "near or toward"; also meaning "added to". [5]
adaxial
The surface of an organ facing toward the organ's axis, [5] e.g. the upper surface of a lateral organ such as a leaf or petal. Contrast abaxial .
adelphia
Plural: adelphiae. A bundle or structure of stamens forming one unit in an adelphous flower; for example, the stamen tube around the pistil of Hibiscus.
adelphous
Having organs, particularly filaments such as stamens, connected into one or more adelphiae, whether in the form of bunches or tubes, such as is commonly seen in families such as Malvaceae. Usage of the term is not consistent; some authors include closely bunched filaments, while others include only adelphiae in which filaments are connected at their bases at least. See for example, Sims: "...the filaments are so closely pressed that they have the appearance of being monadelphous...". [6] Compare derived terms such as monadelphous, having stamens growing in a single bunch or tube, for example in Hibiscus , and diadelphous growing in two bunches.
adherent
Slightly united to an organ of another kind, [5] usually to a part of another whorl, e.g. a sepal connected to a petal. Contrast adnate .
adnate
Grown from or closely fused to an organ of a different kind, [5] especially along a margin, e.g. a stamen fused to a petal. Adnate anthers have their halves attached to the filament through most of their length. (Contrast connate.)
adventitious
Produced in an unpredictable or unusual position, [5] e.g. an adventitious bud produced from a stem rather than from the more typical axil of a leaf. Adventitious roots may develop from nodes of prostrate stems of some plant species, or from the hypocotyl rather than from the radicle of a germinating monocotyledon.
adventive
Introduced accidentally [5] (usually referring to a weed).
aerial
Of the air; growing or borne above the surface of the ground or water. [7]
aestivation
The arrangement of sepals and petals or their lobes in an unexpanded flower bud. Contrast vernation .
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 a single flower, e.g. a blackberry. Compare multiple fruit .
agochoric
Plants that are spread through accidental transport.
agricultural weed
See weed .
agriophyte
Plant species that have invaded native vegetation and could survive there without human intervention. They are established there in natural habitats, remaining part of natural vegetation even after human influence has ceased, and are independent of humans in their continued existence. [8]
agrophic
a comb-like series of veins forking from a single side of a primary or secondary vein
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
(of 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
Any plant introduced to an area outside its natural range. Often used interchangeably or in combination with foreign, exotic , non-native , and non-indigenous .
alkaloid
Any of a loosely defined class of organic compounds found in the tissues of many species of plants. Alkaloid molecules have one or more alkaline-reacting nitrogen atoms in their carbon structures. Many alkaloids are commercially important as drugs or poisons, e.g. caffeine, morphine, quinine, and strychnine, each of which occurs naturally in certain plants.
alternate
1.  (adj.) (of leaves or flowers) Borne singly at different levels along a stem, including spiralled parts. Contrast opposite .
2.  (prep.) Occurring between something else, e.g. stamens alternating with petals.
ament
A synonym of catkin.
amphitropous
(Of an ovule) Bent so that both ends are near each other. Contrast anatropous , campylotropous , and orthotropous .
amplexicaul
With the base dilated and clasping the stem, usually of leaves.
amylum star
a vegetative propagative body filled with starch (amylum) and located around the lower nodes of certain stoneworts.
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
(of an ovule) Inverted so that the micropyle faces the placenta (this is the most common ovule orientation in flowering plants). Contrast amphitropous , campylotropous , and orthotropous .
androdioecious
Having bisexual flowers and male flowers on separate individuals. Contrast andromonoecious , polygamodioecious , polygamomonoecious , and polygamous .
androecium
A collective name for the male reproductive parts of a flower; the stamens of a flower considered collectively. Contrast gynoecium . Abbreviated A; e.g. A 3+3 indicates six 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
Having 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. Contrast androdioecious , gynomonoecious , polygamodioecious , polygamomonoecious , and polygamous .
anemophilous
Adapted to pollination by wind.
anemophily
Adaptation to 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. Contrast isotomic .
annual
A plant that completes its life cycle (i.e. germinates, reproduces, and dies) within a single year or growing season.
annulus
1.  A ring-like structure; in the form of a ring. Pappus bristles are sometimes attached to a ring called an 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 an annulus. Certain flowers have ring-like constrictions at the mouth of the flower, e.g. in Huernia and Aristolochia .
2.  A ring of specialized cells on the sporangium.
anterior
Positioned in front of, toward the apex. Compare distal .
anthemoid
In the Compositae, a style with a brush-like tuft of sweeping hairs at the tip of each style branch.
anther
The pollen-bearing part of a stamen.
antheridium
in bryophytes, a specialised gametophytic organ that produces the male gametes
antheridiophore
In liverworts of the order Marchantiales, a male gametophore, a specialised, stalked structure that bears the antheridia
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.
anthocarp
A type of fruit in which some part of the flower persists attached to the pericarp, e.g. in Nyctaginaceae.
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. Contrast periclinal .
antrorse
Directed toward or upward, e.g. of hairs on a stem. Contrast retrorse .
apetalous
Lacking petals.
apex

pl.apices

The tip; the point furthest from the point of attachment.
aphananthous
(of flowers) Inconspicuous or unshowy, as opposed to phaneranthous or showy.
aphlebia

pl.aphlebiae

Imperfect or irregular leaf endings commonly found on ferns and fossils of ferns from the Carboniferous Period.
apical
At or on the apex of a structure, usually a shoot, a stem, or the trunk of a tree, e.g. an apical meristem or an apical bud.
apiculate
especially of leaves, ending in a short triangular point.
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

adj.apomictic

A type of asexual reproduction whereby viable seeds or spores are produced asexually, without fertilization, such that the genetic material they contain is a clone of the parent's genetic material. 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.
apopetalous
Having separate petals, not fused (sympetalous).
apophyllous
perianth or other segments free, not united. Compare symphyllous, gamophyllous, polyphyllous.
apophysis
1.  The external part of a cone scale.
2.  An outgrowth of an organ or an enlargement of a stem.
appendage
A secondary part attached to a main structure; an external growth that seldom has any obvious function, hence appendiculate.
appendiculate
Having the nature of or bearing appendages.
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 nonetheless been present in a particular geographic area for some time. Contrast neophyte .
archegonium
A multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete. The corresponding male organ is called the antheridium.
archegoniophore
In liverworts of the order Marchantiales, a female gametophore, specialised, stalked structure that bears the archegonia and the sporophytes
arctotoid
In the Compositae, a 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
1.  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.
2.  A structure on the stem node of a cactus; the region of a cactus upon which spines and flowers are borne.
3.  In lichenology, a polygonal piece of a thallus surface where a crustose lichen is 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; e.g. the fronds of certain ferns where they join the rhizome.
ascending
1.  (of a stem) Spreading horizontally, then directed upward; an ascending stem is more or less prostrate near its base, then erect.
2.  (of an ovule) Attached somewhat above the base.
asexual reproduction
Reproduction that does not involve gametes. Often used interchangeably with vegetative reproduction.
asperulous
Having a rough, sandpapery texture, e.g. some leaf surfaces.
asymmetrical
Irregular or unequal; lacking any plane of symmetry; e.g. flowers of Canna .
attenuate
Narrowing gradually.
auricle
An ear-shaped lobe, particularly a small, roundish, lateral appendage of a leaf or leaf-like organ.
awn
1.  Any long, bristle-like appendage.
2.  In the Poaceae, an appendage terminating or on the back of glumes and/or lemmas of some grass spikelets.
3.  In the Geraniaceae, the part of the style that remains attached to the carpel that separates from the carpophore (column).
4.  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.
axils , and an apical bud sprouting from the apex of the shoot of Searsia angustifolia. The axillary buds are dormant in scaly cataphylls, but the apical bud is bare, exposing emerging leaf rudiments.
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, usually referring to the axil of a leaf.
axis
The main stem of a whole plant or inflorescence; also, the line along which this stem extends.

B

Baculiform desmid in genus Closterium Mikrofoto.de-Closterium 5.jpg
Baculiform desmid in genus Closterium
Barbs occur on the spines of some species of cactus, as shown here enlarged. Spine2.jpg
Barbs occur on the spines of some species of cactus, as shown here enlarged.
Berries of Olinia ventosa, including a cross-section showing hard seeds in the pulp Berries of Olinia ventosa IMG 12951304.jpg
Berries of Olinia ventosa , including a cross-section showing hard seeds in the pulp
The bifoliate compound leaves of the Mopane tree, Colophospermum mopane, suggested the common name "butterfly tree". Mopane (Colophospermum mopane) leaves (11683653383).jpg
The bifoliate compound leaves of the Mopane tree, Colophospermum mopane , suggested the common name "butterfly tree".
Cross-section of a silique of Arabidopsis thaliana, showing it to be biloculate, formed of two carpels, morphologically a silique and not a pod Arabidopsis thaliana sl18.jpg
Cross-section of a silique of Arabidopsis thaliana , showing it to be biloculate , formed of two carpels, morphologically a silique and not a pod
Bipinnate leaf of Gymnocladus dioicus Gymnocladus dioicus Berlin Bernauer TP03.jpg
Structure of a biternate compound leaf Leaf morphology type ternately-compound biternate.png
Structure of a biternate compound leaf
This African Baobab tree, Adansonia digitata, has an enormous bole beneath a relatively modest canopy that is typical of this species. Baobab tree.jpg
This African Baobab tree, Adansonia digitata , has an enormous bole beneath a relatively modest canopy that is typical of this species.
The large, colourful bracts of Bougainvillea are commonly mistaken for its petals. Bougainvilea bracts.jpg
The large, colourful bracts of Bougainvillea are commonly mistaken for its petals.
Burrs, fruits of Arctium species Burrdock Seed heads - geograph.org.uk - 1131389.jpg
Burrs , fruits of Arctium species
Buttress root of a mature elm XN buttress root 526.jpg
Buttress root of a mature elm
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 toward the base (i.e. with the youngest toward 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 . Contrast acrophyll .
beak
A prominent, pointed terminal projection, especially of a carpel or fruit.
berry
A type of indehiscent fruit with the seeds immersed in the pulp, e.g. a tomato.
bi-
A prefix meaning "two"; e.g. bisulcate, having two sulci or grooves.
biennial
A plant which completes its life cycle (i.e. germinates, reproduces, and dies) within two years or growing seasons. Biennial plants usually form a basal rosette of leaves in the first year and then flower and fruit in the second year.
bifid
Forked; cut in two for about half its length. Compare trifid .
bifoliate
(of a compound leaf) Having precisely two leaflets, usually in a symmetrical pair, e.g. a leaf of Colophospermum mopane . Compare jugate lobed leaf, e.g. most species of Bauhinia .
bifusiform
Fusiform with a pinch in the middle.
bilabiate
Having two lips, e.g. the form of the petals in many irregular flowers.
bilateral
1.  Having two distinguishable sides, such as the two faces of a dorsiventral leaf.
2.  Arranged on opposite sides, e.g. leaves on a stem; cf. distichous and opposite.
3.  Bilaterally symmetrical, as in a leaf with a symmetrical outline.
biloculate
Having two loculi, e.g. in anthers or ovaries.
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 specific 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 together (not just the second name) constitute the species name.
bipinnate
Doubly pinnate; e.g. 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 occur only on monoecious plants. See also androgynous , monoicous , and plant reproductive morphology.
bitegmic
(of an ovule) Covered by two integuments. Contrast unitegmic .
biternate
Ternate, with each division divided into three.
bivalve
Having two valves or hinged parts. Contrast trivalve .
blade
The lamina or flattened part of a leaf, excluding the stalk or petiole.
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 in which 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; synonymous with bractlet.
bracteolate
Possessing bracteoles (bractlets).
bractlet
See bracteole .
branchlet
A small branch.
brevideciduous
A plant that loses all of its leaves only briefly before growing new ones, 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.
brochus

pl.brochi

Width of one lumen of a pollen grain reticulum and half of the width of the surrounding muri (walls), hence heterobrochate and homobrochate, where the lumina are of different or similar sizes, respectively.
bryophyte
Informally, any plant that is a moss, hornwort, or liverwort. 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 bulbel.
bullate
Having rounded or globular blisters on the surface.
burr
1.  A prickly fruit.
2.  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, e.g. commonly of Ficus macrophylla .
byssoid
A growth form of a lichen thallus that is whispy, like teased wool.

C

Dianthus chinensis has a caespitose growth habit. Dianthus chinensis - Raspberry parfait 3.jpg
Dianthus chinensis has a caespitose growth habit.
Callus tissue of Nicotiana tabacum growing on a nutrient medium in plant tissue culture}} Callus1.jpg
Callus tissue of Nicotiana tabacum growing on a nutrient medium in plant tissue culture}}
Structure of flower of an orchid in genus Praecoxanthus, with the callus labelled Praecoxanthus labelled.pdf
Structure of flower of an orchid in genus Praecoxanthus, with the callus labelled
Bearded callus of a floret of the grass species Chrysopogon filipes Chrysopogon filipes callus (6914259711).jpg
Bearded callus of a floret of the grass species Chrysopogon filipes
Dormant leaf buds of deciduous trees are commonly protected by imbricate cataphylls that are shed when the bud sprouts. Leaf bud of American Sweet gum (Liquidambar styraciflua) showing imbricate cataphylls 5405.jpg
Dormant leaf buds of deciduous trees are commonly protected by imbricate cataphyll s that are shed when the bud sprouts.
Male catkins of Betula pendula Betula pendula male catkins 2.jpg
Male catkins of Betula pendula
The caudex of Dioscorea elephantipes grows largely above the soil surface. Many species that form caudices grow them underground. Dioscorea elephantipes.JPG
The caudex of Dioscorea elephantipes grows largely above the soil surface. Many species that form caudices grow them underground.
Moehringia growing as a chasmophyte on an overhanging cliff Moehringia Vilin razboj 2.JPG
Moehringia growing as a chasmophyte on an overhanging cliff
Chloroplasts within the cells of the leaves of the moss Bryum capillare Bryum capillare leaf cells.jpg
Chloroplasts within the cells of the leaves of the moss Bryum capillare
Not all chloroplasts are simple in shape. Chloroplasts of Spirogyra are helical within the tubular cells of their algal filaments. The freshwater alga Spirogyra.jpg
Not all chloroplasts are simple in shape. Chloroplasts of Spirogyra are helical within the tubular cells of their algal filaments.
Circinate vernation of crosiers of the fern Sadleria cyatheoides Sadleria cyatheoides unfurling.jpg
Circinate vernation of crosiers of the fern Sadleria cyatheoides
The so-called "fleshy leaves" of cacti such as this Opuntia tomentosa are actually cladodes, branches. The true leaves are the spines growing on the cladodes, which on this young cladode are still fleshy. New cladode and bud of Velvet Tree Pear, Opuntia tomentosa (10921285475).jpg
The so-called "fleshy leaves" of cacti such as this Opuntia tomentosa are actually cladodes , branches. The true leaves are the spines growing on the cladodes, which on this young cladode are still fleshy.
Colony of cells forming a coenobium, of an alga in the genus Pediastrum Pediastrum minus 1.jpg
Colony of cells forming a coenobium , of an alga in the genus Pediastrum
Asclepias syriaca seeds, showing the coma of hairs in its pappus Asclepias syriaca (fruits and seeds) D130902 closeup.jpg
Asclepias syriaca seeds, showing the coma of hairs in its pappus
Curcuma pseudomontana with red coma bracts Curcuma pseudomontana.JPG
Curcuma pseudomontana with red coma bracts
Pfaffia gnaphalioides flowers with basal coma hairs Pfaffia gnaphalioides- Soriano, Palmar, Suelo arenoso pedregoso al margen del Lago.JPG
Pfaffia gnaphalioides flowers with basal coma hairs
Coma atop Muscari armeniacum, bearing sterile flowers Muscari armeniacum flowerhead3 ST (14999577633).jpg
Coma atop Muscari armeniacum , bearing sterile flowers
The conical compound inflorescence of Aeonium arboreum is a compound panicle composed of minor panicles, some of which are compound in their turn. Aeonium arboreum - Jardin Botanico Canario Viera y Clavijo - Gran Canaria - 03.jpg
The conical compound inflorescence of Aeonium arboreum is a compound panicle composed of minor panicles, some of which are compound in their turn.
California buckeye (Aesculus californica) has a compound palmate leaf, the leaflets radiating from a central point. Aesculus californica-12.jpg
California buckeye ( Aesculus californica ) has a compound palmate leaf, the leaflets radiating from a central point.
The lobes of the gamopetalous corolla of Nicotiana flowers are conduplicate in the bud. Nicotiana x sanderae flowers.jpg
The lobes of the gamopetalous corolla of Nicotiana flowers are conduplicate in the bud.
Casuarina equisetifolia male and female flowers and cones Starr-170624-0907-Casuarina equisetifolia-male and female flowers and cones-Abandoned Runway Near Rusty Bucket Sand Island-Midway Atoll (36059371970).jpg
Casuarina equisetifolia male and female flowers and cones
Gamopetalous Watsonia flower split open between two petals to show the connate formation of the corolla tube. Compare the adnate attachment of the stamen bases to the matching petals. Watsonia flower with adnate stamens and connate petals IMG 1974c.jpg
Gamopetalous Watsonia flower split open between two petals to show the connate formation of the corolla tube. Compare the adnate attachment of the stamen bases to the matching petals.
Corms, one entire in its tunic, one partly peeled to show tunic cataphylls, and one split to show inner structure Corms of Crocosmia, entire, partly peeled, and split.jpg
Corms, one entire in its tunic, one partly peeled to show tunic cataphylls, and one split to show inner structure
The corona of this Passiflora flower is a ring of purple filaments between the petals and the stamens. Passiflora kermesina3.jpg
The corona of this Passiflora flower is a ring of purple filaments between the petals and the stamens.
Cotyledons of seedlings of Koelreuteria. One plant shows the first new leaves above its cotyledons; the rest show various younger stages of emerging cotyledons. Koelreuteria paniculata - cotyledons and first true leaves, 2.jpg
Cotyledons of seedlings of Koelreuteria. One plant shows the first new leaves above its cotyledons; the rest show various younger stages of emerging cotyledons.
Crassula rupestris frequently grows as a cremnophyte on cliff faces in fynbos. Crassula rupestris on cliff face - Cape Town.jpg
Crassula rupestris frequently grows as a cremnophyte on cliff faces in fynbos.
Nymphoides crenata has crenate leaf margins. Nymphoides crenata leaf1 (16826924328).jpg
Nymphoides crenata has crenate leaf margins.
Crustose lichens on a wall N2 Lichen.jpg
Crustose lichens on a wall
Mimetes cucullatus, so named for the hooded, cucullate shape of its white flowers Mimetes cucullatus 0147.jpg
Mimetes cucullatus, so named for the hooded, cucullate shape of its white flowers
Murraya paniculata has leaves with cuneate (wedge-shaped) bases. Murraya paniculata (333).JPG
Murraya paniculata has leaves with cuneate (wedge-shaped) bases.
Examples of cupules of Fagaceae:
A: Quercus rubra B: Quercus trojana
C: Fagus sylvatica D: Castanea sativa Cupule of Fagaceae.jpg
Examples of cupules of Fagaceae:
A: Quercus rubraB:Quercus trojana
C:Fagus sylvaticaD:Castanea sativa
Cuspidate leaves of Diplacus bigelovii var. cuspidatus Diplacus bigelovii (A. Gray) A. Gray var. cuspidatus A. L. Grant 20000508 01.jpg
Cuspidate leaves of Diplacus bigelovii var. cuspidatus
Euphorbia milii is commercially grown for the aesthetic appearance of its brightly colored, bract-like structures called cyathophylls, which sit below the inflorescence. Euphorbia Milii flowers.jpg
Euphorbia milii is commercially grown for the aesthetic appearance of its brightly colored, bract -like structures called cyathophyll s, which sit below the inflorescence .
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 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, e.g. the sepals of poppies, which fall off when the petals begin to open. Compare persistent and fugacious .
caespitose
Tufted or turf-like, e.g. the growth form of some grasses.
calcarate
possessing a spur.
calcareous
A soil type or a lichen substrate rock type that is rich in or largely composed of calcium carbonate.
callose
Hardened; thickened; callous.
callus

pl.calli

1.  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 other sepals or calyx lobes retain their original size. More extreme than an accrescent calyx, calycophylls are found in Rubiaceae. Compare semaphyll and pterophyll .
calyculate
Having an epicalyx.
calyculus
1.  A cup-shaped structure formed from bracts resembling an outer calyx.
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.
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 embryo sac. Compare amphitropus , anatropous , and 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.  A tube, pore or passage with a narrow, internal cross-section.
2.  Slender; hair-like.
capitate
1.  (of an inflorescence) Having a knob-like head, with the flowers unstalked and aggregated into a dense cluster.
2.  (of a stigma) Like the head of a pin.
capitulum
A dense cluster of sessile or subsessile flowers or florets, e.g. a flower head in the daisy family, Asteraceae. See 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 the Asteraceae, having a 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.
carneous
Flesh-coloured, especially as applied to some flowers.
carnose, carnous
Fleshy or pulpy in texture, especially as applied to some tissues or organs. Contrast coriaceous and corneous .
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. Compare corneous and coriaceous .
caruncle
A small piece of flesh-like tissue, typically lumpy or warty, growing on the testa near the hilum. Contrast aril .
caryopsis
A dry, indehiscent, one-seeded fruit in which the seed coat is closely fused to the fruit wall, e.g. 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.
cassideous
Hood-, helmet- or bonnet-shaped; generally referring to floral anatomy, e.g. in the flowers of Aconitum , Satyrium , etc.
casual alien
An exotic plant that appears with no apparent human assistance but does not develop a sustained population(s), or one that persists only by repeated new introductions. Compare alien .
cataphyll
Any plant structure which is morphologically a leaf but which has at most an incidental or transient photosynthetic function. They are either shed when their main function has been completed, or are incorporated into structures where, when dead, they serve a protective or supportive purpose.
catenulate
In the shape of a chain; formed of parts or cells connected as if chained together, e.g. some diatoms, algae, and cyanobacteria such as Anabaena . See also concatenate .
catkin
A spike, usually pendulous, in which the mostly small flowers are unisexual and without a conspicuous perianth, e.g. in willows, poplars, oaks, and casuarinas. The individual flowers often have scaly bracts and are generally wind-pollinated. Catkins are usually shed as a unit.
caudate
Having a narrow, tail-like appendage or tip, e.g. a drip tip. Contrast acuminate , cuspidate , and mucronate .
caudex

pl.caudices

The stem of a plant, especially a woody one; also used to mean a rootstock, or particularly a basal stem structure or storage organ from which new growth arises. Compare lignotuber .
caudiciform
Stem-like or caudex-like; sometimes used to mean "pachycaul", meaning "thick-stemmed".
caulescent
possessing a well-developed stem above ground, similar to cauline. Antonym of acaulescent (lacking an apparent stem)
cauline
Borne on an aerial stem or caulis, as with leaves, flowers, or fruits (when applied to the latter two organs, usually referring to older stems; synonymous with 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.
cenanthous
(of a perianth) Lacking both stamens and pistil, i.e. a flower with neither androecium nor gynoecium.
centrifixed
Of a two-branched organ attached by its centre, e.g. a hair or anther.
ceraceous
Having a waxy appearance, colour, or texture, e.g. flowers of many species of Ceropegia , and the waxy fruit of some species of Myrica .
cernuous
Nodding, falling headlong or face down; inclined, stooping, or bowing forward. Applied to many species with a nodding, stooping habit, such as many Narcissus and Dierama species. Many plant species bear the specific epithet "cernua".
cespitose
An alternative spelling of caespitose, meaning Tufted or turf-like, e.g. the growth form of some grasses.
chamber
A cavity of an ovary.
channelled
Sunken below the surface, resulting in a rounded channel.
chartaceous
Having a papery texture.
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 . [9] [10]
chimera
An individual composed of two or more genetically distinct tissues, most commonly as a result of a graft and sometimes by mutations that occur during cell division or cellular transfers during seed development.
chiropterophilous
Pollinated by bats.
chlorophyll
Any of a variety of different chemical pigments in chloroplasts that are 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.
cirrhose
(of a leaf) Ending in a tendril at the apex.
cladode
A photosynthetic branch or 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.
clavuncula
In the Apocynaceae, an enlarged, drum-shaped stigma of which the sides and lower surface are the receptive zones. Coherent with the anthers or not.
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 which 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 asexual vegetative reproduction of a parent plant, with both plants having identical genetic compositions.
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.
coleoptile
One type of sheath in the structure of monocotyledonous seeds. The coleoptile is a protective sheath or cap (pileus), generally more or less pointed, that covers the monocotyledonous plumule as it emerges from the soil. It generally turns green and contributes to photosynthesis until its function is superseded by the main growth of the seedling. Contrast this with the coleorhiza, which remains underground until it is superseded as the roots emerge.
coleorhiza
One type of sheath in the structure of monocotyledonous seeds. The coleorhiza connects the coleoptile to the radicle and protects the monocotyledonous radicle during germination. Unlike the coleoptile, the coleorhiza is associated with the root and does not emerge from the soil during germination. Contrast coleoptile .
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 the ovary and incorporating the style and stamens also known as the gynostegium, e.g. in orchids and milkweeds.
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.
coma
1.  A tuft of hairs from testa or funiculus at one or both ends of some seeds, e.g. in Strophanthus , Asclepias , or Alstonia .
2.  Sterile bracts, e.g. in Curcuma , Ananas , or Eucomis .
3.  Sterile flowers, e.g. in Muscari and Leopoldia , at the apex of some inflorescences.
4.  A tuft of hairs at the base of some flowers, e.g. in Pfaffia gnaphalioides.
5.  A tuft of hairs at the apex or base of some spikelets.
6.  An axil tuft of hairs in inflorescences in some Poaceae, e.g. in Eragrostis comata .
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. See also fissure and suture.
community
An ecological assemblage of plants that characteristically occur together.
compound
Composed of several parts, e.g. a leaf composed of multiple leaflets, a gynoecium composed of multiple carpels, or an inflorescence made up of multiple 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. Compare palmate .
compressed
Flattened lengthwise, either laterally (from side to side) or dorsally (from front to back).
concatenate
Joined together in a chain-like form. See also concatenate and catenate .
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 type of 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 gamopetalous 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 or 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. See 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.
corcle
A plant embryo, plumule, or plumule plus radicle.
cordate
Heart-shaped, with the notch lowermost; of the base of a leaf, like the notched part of a heart. Contrast obcordate .
coriaceous
Leathery; stiff and tough, but flexible. Compare corneous .
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".
corneous
Horny in texture; stiff and hard, but somewhat tough. Compare coriaceous .
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 or 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 . [9] [10]
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.
cryptogam
Any of the "lower plants" which produce spores and do not have stamens, ovaries, or seeds; literally, plants whose sexual reproductive organs are not conspicuous. This group 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, extending 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 (either 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, e.g. Rubus nitidoides 'Merton Early'. 'Merton Early' is the cultivar epithet.
cuneate
Wedge-shaped, with straight sides converging at a 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 hard, pointed tip, stiffer and more formidable than a mucro, 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 asexual vegetative propagation.
cyathium

pl.cyathia

An inflorescence of unisexual flowers surrounded by involucral bracts, especially the flowers of Euphorbia .
cyathophyll
In Euphorbia , the bract-like structure 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).
cymose
Having a cyme or cymes.
cypsela
A type of dry, one-seeded, indehiscent fruit formed from an inferior ovary.

D

Seasonal, healthy decortication of Eucalyptus grandis outer bark Eucalyptus grandis bark decorticating 7th Brigade Park Chermside L1100307.jpg
Seasonal, healthy decortication of Eucalyptus grandis outer bark
A decorticating machine collecting fibre from leaves Descripcion General-V150.jpg
A decorticating machine collecting fibre from leaves
Decussate phyllotaxis of Crassula rupestris Crassula rupestris-PICT3087.jpg
Dentate leaf of elm Princeton leaf.JPG
Dentate leaf of elm
Denticulate leaves of Ziziphus mauritiana Ziziphus mauritiana Lam - Flickr - lalithamba.jpg
Astragalus austriacus is regarded as diadelphous because it has one stamen unattached to the main adelphia (bunch). Astragalus austriacus sl18.jpg
Astragalus austriacus is regarded as diadelphous because it has one stamen unattached to the main adelphia (bunch).
The paired cotyledons of a castor bean seedling (Ricinus communis) are typical of a dicotyledon. Young castor bean plant showing prominent cotyledons.jpg
The paired cotyledons of a castor bean seedling ( Ricinus communis ) are typical of a dicotyledon .
Discolorous leaves of Brachylaena discolor differ in colour between their upper and lower surfaces. Brachylaena discolor Brachylaena uniflora leaves both.JPG
Discolorous leaves of Brachylaena discolor differ in colour between their upper and lower surfaces.
Disk florets opening in a capitulum of a cultivated Helianthus. They open progressively from the edge to the centre of the disk. Sonnenblume Helianthus 2.JPG
Disk florets opening in a capitulum of a cultivated Helianthus . They open progressively from the edge to the centre of the disk.
Dissepiment developing in tissue of carpels where they meet to form locules in the capsule of the ovary of Lilium Dissepiment label added to file of Jon Houseman.jpg
Dissepiment developing in tissue of carpels where they meet to form locules in the capsule of the ovary of Lilium
Boophone disticha has conspicuously distichous leaves. Boophone disticha, habitus, Skeerpoort, a.jpg
Boophone disticha has conspicuously distichous leaves.
Domatia at the bases of the thorns of Acacia drepanolobium, the "Whistling Thorn". Note the access holes. Acacia drepanolobium-- Whistling Thorn (25396927222).jpg
Domatia at the bases of the thorns of Acacia drepanolobium, the "Whistling Thorn". Note the access holes.
Dorsiventral (bilateral) leaves of Syzygium gerrardii and Triadica sebifera Dorsiventral (bilateral) leaves of Syzygium gerrardii and Triadica sebifera IMG 1994c.jpg
Dorsiventral (bilateral) leaves of Syzygium gerrardii and Triadica sebifera
Leaves of Epipremnum aureum have a cuspidate drip tip. Epipremnum pinnatum var.jpg
Leaves of Epipremnum aureum have a cuspidate drip tip .
deciduous
Dehiscing and falling seasonally, as with bark, leaves, or petals. Contrast persistent .
declinate
Curving downward, and then upward 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 would otherwise be a pinnate leaf are themselves pinnately divided.
decorticate
1.  (intr. v.) To shed the outer bark of a tree, usually seasonally as part of the natural growth cycle.
2.  (tr. v.) To strip the peel, crust, bark, or other surface tissues from a plant or from harvested material, such as in extracting fibre from harvested Agave leaves.
decumbent
Having branches growing horizontally along the ground but which are turned up at the ends.
decurrent
Extending downward beyond the point of insertion, e.g. when the base of a leaf or a fungal gill is prolonged downward along the stem in a raised line or narrow wing.
decussant
A synonym of decussate; the usage decussant is questionable and occurs rarely, probably as an error. The formally correct usage is decussate.
decussate
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 petals or sepals (or less), or an inflorescence ending in a flower or an aborted floral bud, typically a cymose inflorescence. Contrast indefinite .
deflexed
Bent downward. Contrast 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. Contrast 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. Contrast indeterminate .
diadelphous
Referring to a class of adelphous structure in which the stamens or similar organs are connected in two adelphiae instead of just one.
diaspore
Any reproductive part of a plant adapted for dispersal and for establishing new plants; may be a disseminule such as a seed, or other parts such as specialised buds, branches, inflorescences, or fruits.
dichasium
A cymose inflorescence with all branches below the terminal flower in regular opposite pairs. Compare monochasium and pleiochasium .
dichlamydeous
Having a perianth which is divided into a separate calyx and corolla. Compare homochlamydeous .
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 venation patterns on leaves, the thorns of various species of Carissa (which morphologically are branches), and the thalli or hyphae of various algae and fungi.
dicotyledon

Also abbreviated dicot.

A flowering plant whose embryo has two or more cotyledons (seed leaves). Contrast monocotyledon .
digitate
With segments spreading from a common centre, like the fingers of a hand. See also palmate and palmatisect .
digitiform
shaped like a finger.
dimorphic
Occurring in two different forms (with respect to shape and/or size), e.g. of stamens, fronds, or leaves. See also monomorphic (having a single form) and polymorphic (having many forms).
dioecious
(of vascular plants) Having male and female reproductive structures which develop only on different individuals and never on the same individual. Contrast monoecious.
dioicous
(of a bryophyte gametophyte) Having male and female reproductive structures which develop only on different individuals and never on the same individual. Contrast monoicous .
diploid
Having two complete sets of chromosomes in the nucleus of a sporophyte cell, i.e. one set from each of the parental gametes. This is often expressed symbolically as 2n, where n = the number of chromosomes in the haploid gamete.
diplostemonous
Having stamens arranged in two whorls, with the outer whorl alternating with the petals while the inner whorl is opposite the petals. Compare obdiplostemonous and haplostemonous .
disc

Also spelled disk.

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) Having upper and lower surfaces of different colours.
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 with sufficient distance so as to preclude gene flow between them.
disk floret
A floret occurring most typically in the disk of the capitulum of flowers in the family Asteraceae, and to some extent in other plants that bear a flowering head with a disk, such as Scabiosa .
dissected
Deeply divided; cut into many segments.
dissepiment
A partition or septum in a plant part, usually referring to septa between the loculi of capsules or of other fruits with multiple partitions.
distal
Remote from the point of origin or attachment; the free end. Contrast 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. Compare 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. "Division" is generally used only for plants, and is the approximate botanical equivalent of the term 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
From Latin dorsum, a ridge or the back of an animal. Partly because the term originally referred to animals rather than plants, usage in botany is arbitrary according to context and source. In general "dorsal" refers to "the rear or back or upper surface", but in botanical usage such concepts are not always clearly defined and may be contradictory. For example:
  • facing away from the axis (abaxial) in a lateral organ of an erect plant
  • facing away from the substrate in any part of an erect plant, for example the upper surface of a more or less horizontal leaf (adaxial) or the upper part of the crown of the plant
  • facing away from the substrate in a prostrate or climbing plant or floating leaves such as those of Nymphaea.
Derived or related terms include dorsad, "toward the dorsal", and dorsum, "the dorsal part of the organ or organism as a unit". Related anatomical terms of location include ventral, lateral.
dorsifixed
Attached at or by the back, e.g. anthers on a filament.
dorsiventral
Having structurally and visibly different upper and lower surfaces, e.g. some leaves. Compare bilateral and isobilateral .
drip tip
A long, narrow, acuminate, caudate, or cuspidate extension at the tip of a leaf or leaflet. Commonly an adaptation to rainy conditions, as it promotes shedding of water by its dripping from the narrow tip. The term "drip tip" is not anatomically descriptive in the way that say, acuminate or cuspidate, are; rather it is a description of the functional shape that aids dripping, irrespective of the specific geometry of the shape itself.
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

Plants of the genus Corydalis bear seeds with attached elaiosomes, which have various functions, commonly attracting ants. On some Corydalis species, elaiosomes that attract ants also repel mice. Corydalis cheilanthifolia pod.jpg
Plants of the genus Corydalis bear seeds with attached elaiosomes , which have various functions, commonly attracting ants. On some Corydalis species, elaiosomes that attract ants also repel mice.
Petals of Heracleum sphondylium are variously emarginate at their tips--flowers in the middle of the inflorescence have slightly emarginate petals, whereas flowers at the periphery are so deeply emarginate as to be almost cleft in two. Heracleum sphondylium 003.JPG
Petals of Heracleum sphondylium are variously emarginate at their tips—flowers in the middle of the inflorescence have slightly emarginate petals, whereas flowers at the periphery are so deeply emarginate as to be almost cleft in two.
The pale embryo emerging from the upper surface of the sprouting date seed is tiny in comparison to the endosperm, its main food supply, which comprises almost all of the rest of the seed. Date Seed sprouting.jpg
The pale embryo emerging from the upper surface of the sprouting date seed is tiny in comparison to the endosperm , its main food supply, which comprises almost all of the rest of the seed.
Water lilies and reeds represent two ecological categories of emergent aquatic vegetation. Water lilies and reeds, Lochan Dubh - geograph.org.uk - 233467.jpg
Water lilies and reeds represent two ecological categories of emergent aquatic vegetation.
Iris pseudacorus has clearly ensiform leaves: narrow, straight-edged, sword-shaped. IrisPseudacorus 6004.JPG
Iris pseudacorus has clearly ensiform leaves: narrow, straight-edged, sword-shaped.
The enlarged calyx and smaller epicalyx of Hibiscus sabdariffa Terengganu roselle.jpg
The enlarged calyx and smaller epicalyx of Hibiscus sabdariffa
Shoots from epicormic buds on Eucalyptus following a bushfire Epicormic Shoots from an Epicormic Bud on Eucalyptus following Bushfire 2, near Anglers Rest, Vic, Aust, jjron 27.3.2005.jpg
Shoots from epicormic buds on Eucalyptus following a bushfire
An epilithic lichen Xanthoparmelia angustiphylla.jpg
An epilithic lichen
Tillandsia recurvata growing as a harmless, non-parasitic epiphloedal epiphyte on a tree trunk that is also infested with an epiphloedal foliose lichen Tillandsia recurvata epiphyte IMG 1620.jpg
Tillandsia recurvata growing as a harmless, non-parasitic epiphloedal epiphyte on a tree trunk that is also infested with an epiphloedal foliose lichen
Seeds or fruits are dispersed by epizoochory when they stick to the fur of animals. Epizoochoria NRM.jpg
Seeds or fruits are dispersed by epizoochory when they stick to the fur of animals.
The bases of equitant leaves enclose later leaves on the stem. Boophane disticha in Phipps Conservatory & Botanical Gardens.jpg
The bases of equitant leaves enclose later leaves on the stem.
Sections of exalbuminous seeds Cut of seeds with hypogeal germination.jpg
Sections of exalbuminous seeds
Aloe marlothii flowers with stamens and stigmata of mature flowers exserted from the mouths of the floral tubes Aloe marlothii02.jpg
Aloe marlothii flowers with stamens and stigmata of mature flowers exserted from the mouths of the floral tubes
-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
Of or influenced by the soil.
elaiosome
An external structure attached to the seed of many species of plants. Elaiosomes generally look fleshy and in some species they are rich in oils or other nutritious materials. Their functions vary and are not always obvious; commonly they attract ants or other animals that aid in dispersal, but they may also repel other animals from eating the seed. [11]
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 that is elliptical in all sections through the long axis.
elliptical

Also 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, among aquatic plant species, one that bears flowers and commonly leaves above the surface of the water. Aquatic examples include water lilies, reeds, and papyrus. Some pondweeds such as Stuckenia are not emergent until they flower, at which time only their flowers appear above the water surface.
enantiostyly
The condition in which the gynoecium protrudes laterally, to the right (dextrostyly) or to the left (sinistrostyly) of the androecium, e.g. 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

Also endophloeodal.

(of crustose lichens) Having the thallus growing within rather than upon the bark of trees. [12] :159 Compare epiphloedal and corticolous (growing on the surface of wood or bark) and endolithic (growing within rock).
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 prothallus within the embryo sac.
endospory
The production of spores that germinate into a reduced multicellular gametophyte contained within the spore wall. Contrast exospory .
ensiform
Shaped like the blade of a sword.
entire
1.  Not divided.
2.  (of a margin) Smooth and not lobed or toothed (though possibly wavy or scalloped).
entomophily
A form of pollination whereby pollen or spores are distributed by insects.
epecophyte
Species of recent appearance, usually numerous and constant in the country, but confined to artificial habitats, such as meadows and ruderal vegetation and are dependent on humans for existence. [13]
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 (necral) tissue above the surface of the cortex of a lichen.
epipetalous
Of stamens that are attached to the petals.
epipetric
Growing on rock or stone, lithophytic, epilithic.
epiphloedal
Growing on the surface of bark. Contrast endophloedal (growing inside, not on, the bark) and epilithic (growing on rock, not bark).
epiphyte
A plant, alga or fungus that grows on another plant without deriving nourishment from it but using it for support.
epiphytic
Of an epiphyte; living on the surface of a plant. Compare epilithic , lithophytic .
episepalous
Of stamens that are attached to the sepals.
epitepalous
Of stamens that are attached to the tepals.
epithet
The adjectival component in a binomial scientific name, usually more specifically called a specific epithet; 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. The simplest and commonest example is the second word in a two-word name of a species, such as "mirabilis" in Welwitschia mirabilis .
epizoochory
A type of seed dispersal that occurs when seeds or fruits 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) and 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.
ethelochoric
Deliberate introduction by seedlings, seeds or plants in a new habitat by humans.
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).
exalbuminous
In seeds of a given species, having no endosperm, i.e. no albumen, e.g. in Fabaceae and Combretaceae.
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. Contrast 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 toward the outside of the flower. Contrast introrse and latrorse .

F

Astragalus falcatus has conspicuously falcate pods; not many falcate anatomical structures are so markedly curved. Astragalus falcatus (7441409300).jpg
Astragalus falcatus has conspicuously falcate pods; not many falcate anatomical structures are so markedly curved.
Rhigozum obovatum bears its leaves in well-defined fascicles. Rhigozum obovatum 8217s.jpg
Rhigozum obovatum bears its leaves in well-defined fascicles.
Favolaschia calocera, the orange pore fungus, has conspicuously faveolate fruiting bodies. Orange Pore Fungus (Favolaschia calocera) (33327394770).jpg
Favolaschia calocera , the orange pore fungus, has conspicuously faveolate fruiting bodies.
Emerging leaves of Oldenburgia grandis are heavily felted. Oldenburgia grandis Felted emerging leaf IMG 5836.JPG
Emerging leaves of Oldenburgia grandis are heavily felted .
Fenestrate leaves of Darlingtonia californica Darlingtonia californica ne1 (crop).jpg
Digitalis ferruginea owes its specific name to its ferruginous (rust-coloured) flowers. Digitalis ferruginea-IMG 9992.jpg
Digitalis ferruginea owes its specific name to its ferruginous (rust-coloured) flowers.
Calochortus fimbriatus has fimbriate flowers. Calochortus fimbriatus open flower.jpeg
Panaeolus cinctulus has gently flexuous stipes. Panaeolus cinctulus (Bolton) Britzelm 447936.jpg
The pseudanthium of Zinnia elegans is typical of many Asteraceae in that it includes two types of florets, ray florets and disk florets. Zinnia elegans of Kadavoor.jpg
The pseudanthium of Zinnia elegans is typical of many Asteraceae in that it includes two types of florets, ray florets and disk florets.
The foliose thallus of the lichen Parmotrema tinctorum is leafy. Parmotrema tinctorum umenokigoke01.jpg
The foliose thallus of the lichen Parmotrema tinctorum is leafy.
Medicago sativa (alfalfa or lucerne) is an agriculturally important forb, grown in large volumes for forage, soil improvement, and other purposes. Medicago sativa plant1 (10603928013).jpg
Medicago sativa (alfalfa or lucerne) is an agriculturally important forb , grown in large volumes for forage, soil improvement, and other purposes.
Foveolate seeds of Physochlaina physaloides Seeds of Physochlaina physaloides.jpg
Foveolate seeds of Physochlaina physaloides
Letharia vulpina is a fruticose lichen. Letharia vulpina JHollinger crop.jpg
Letharia vulpina is a fruticose lichen.
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.
farina
powdery, pale yellow crystalline secretion consisting of flavonoids in Primula and other species
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.
female flower
See pistillate flower.
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.  The stalk of a stamen.
2.  Any very narrow, thread-like structure that is 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.
flexistyly
Depending on the degree of maturation of the stamens, the style moves up or down (cataflexistyle or (ana-)hyperflexisyle).
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 grasses and the pseudanthia of daisies.
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
Leaf-like; 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 toward each end; spindle-shaped.

G

Galbulus (berry-like, fleshy) cones on the coniferous tree Podocarpus elatus Podocarpus elatus foliage & cones.JPG
Galbulus (berry-like, fleshy) cones on the coniferous tree Podocarpus elatus
Gametophores (red male antheridia and brown female archegonia) borne on a gametophyte of a Chara species of green algae CharaV3.jpg
Gametophores (red male antheridia and brown female archegonia) borne on a gametophyte of a Chara species of green algae
Longitudinal section of immature male pine cone, showing male gametophytes (pollen grains) developing between the cone scales Male Gametophyte Male Gametophyte Pinus Staminate Zoomed.jpg
Longitudinal section of immature male pine cone, showing male gametophytes (pollen grains) developing between the cone scales
Glandular hairs on the stem of Geranium dissectum Geranium dissectum sl11.jpg
The leaves, buds, and young stalks of Eucalyptus macrocarpa are glaucous, covered with a thick waxy pruinosity. Eucalyptus macrocarpa buds.jpg
The leaves, buds, and young stalks of Eucalyptus macrocarpa are glaucous , covered with a thick waxy pruinosity.
Glochids at the base of an Opuntia cactus spine Opuntia cactus spine and glochids.jpg
Glochids at the base of an Opuntia cactus spine
Glumes of a grass species with a fairly large inflorescence Urochloa mosambicensis spikelet12 annotated - Flickr - Macleay Grass Man.jpg
Glumes of a grass species with a fairly large inflorescence
Scanning electron micrograph of a stoma on the leaf of Haemanthus. The two lip-shaped cells on either side of the pore are the guard cells. Stoma.jpg
Scanning electron micrograph of a stoma on the leaf of Haemanthus . The two lip-shaped cells on either side of the pore are the guard cells.
Drops of guttation fluid on the dentate points fringing the immature leaf of a grapevine Weinblatt13-05.JPG
Drops of guttation fluid on the dentate points fringing the immature leaf of a grapevine
Examples of gymnosperms

LEFT
1-Welwitschia mirabilis
2-Cycas revoluta
3-Taxus baccata
4-Ginkgo biloba
RIGHT
1-Cupressus sempervirens
2-Sequoiadendron giganteum
3-Agathis dammara
4-Araucaria heterophylla }} Gymnospermae.jpg
Examples of gymnosperms
LEFT
1- Welwitschia mirabilis
2- Cycas revoluta
3- Taxus baccata
4- Ginkgo biloba
RIGHT
1- Cupressus sempervirens
2- Sequoiadendron giganteum
3- Agathis dammara
4- Araucaria heterophylla }}
galbulus
In gymnosperms, a fleshy cone (megastrobilus); chiefly relates to cones borne by junipers and cypresses, which are often mistakenly called berries.
galea
An overhanging, helmet-shaped, structure that protects the reproductive parts from precipitation, wind or unwanted visitors.
gall
Abnormal outgrowth on external plant tissues, caused by various parasites, from viruses, fungi and bacteria, to other plants, insects and mites.
gamete
A cell or nucleus that fuses with another of the opposite sex during sexual reproduction.
gametophore
Specialized structures on the gametophytes of some bryophyte species, for example many species in the order Marchantiales; in such species the gametes are produced on the gametophores, which amount to sex organs.
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.
gamopetalous
with joined or fused petals
gamophyllous
a single perianth-whorl of united segments. Compare symphyllous (synonym), apophyllous, polyphyllous
gemma
an asexual reproductive structure found in liverworts and mosses.
gene pool
The complete range of genetic variation found within a population.
genus

pl. genera

A group of one or more 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; glabrate.
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
Describes the external surface of a plant part that has a whitish covering, in some cases with a blueish cast. Often applied to plants with a woolly or arachnoid surface, but properly referring to pruinose surfaces, meaning those with a waxy bloom. The surface of the young leaves of many eucalypts provide good examples, and so do some xerophytes.
globose

Also globular.

Roughly spherical. See also subglobose.
globulose
Approximately spherical.
glochid
A tiny barbed hair or bristle, e.g. the fine defensive hairs in cactus species such as 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 of 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:
  1. an assemblage of two or more cultivars within a species or hybrid;
  2. plants derived from a hybrid in which one or more of the parent species is not known or is of uncertain origin;
  3. 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 reproductive parts of a flower or for the carpels of a flower, whether united or free. Contrast 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.
gynostegium
A compound organ in milkweeds (Asclepiadaceae) and orchids formed by fusion of the filaments of the stamens with the style. Also known as the