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| A- L | N – Z |
Midrib: the central leaf vein which runs from the base to the apex. (Also applied to leaf-like structures.)
Naturalised: a species in a new locality (spread beyond its perceived original distribution), which produces new generations in the new locality without direct human intervention.
Node: the portion (‘joint’) of a stem from which a leaf arises.
Nut: a one-seeded, hard, bony fruit.
Oblanceolate: a shape (usually referring to leaves) which is tapered to a point at both ends but broadens towards the apex.
Oblong: an (approximately) right-angled, 4-sided shape; longer than broad with opposite sides (roughly) parallel; often rounded near the ends.
Obovate: a roughly elliptical shape with the terminal half broader than the basal.
Organ: a visibly differentiated part of a plant which performs specific functions.
Outbreeding: mating of not closely related individuals (opp. inbreeding).
Ovary: the basal part of the female organ (carpel(s)) of a plant in which seeds develop.
Ovate: an oval shape (like a longitudinal section through an egg shape; broader at the base than the apex).
Ovoid: egg-shaped (applied to 3-dimensional forms).
Oxalate: salt of oxalic acid (H2C201); common in plants. Soluble oxalates can be toxic to humans and animals.
Palea: the upper (inner) bract (with the lower, inner lemma) enclosing other floral parts of grasses.
Palmate: lobed, divided or ribbed like the palm of a hand.
Panicle: a branched inflorescence which is composed of racemes.
Pappus: a tuft of hairs or bristles; often on the ‘seeds’ (achenes) of plants in the Asteraceae family.
Parasite: an organism living in or deriving nourishment from another organism (adj. parasitic).
Pedicel: a stalk of a single flower, or grass spikelet (adj. pedicellate).
Peduncle: a stalk of an inflorescence or solitary flower (adj. pedunculate).
Pendulous: drooping, hanging downward.
Perennial: living for more than two years.
Perianth: the calyx (sepals) and corolla (petals) collectively, especially when appearing similar or combined in one structure.
Petal: one unit of the inner bracts (corolla) in a flower; often showy.
Petiole: the stalk of a leaf (adj. petiolate).
Petiolule: the stalk of a leaflet in a compound leaf.
Photosensitisation: sensitivity of lightly pigmented skin to sunlight. Can be induced in animals by consumption of certain plant species.
Pinnate: the arrangement of leaflets (in a compound leaf) on opposite sides of a common axis (rhachis).
Pinnatisect: cut into lobes on both sides of the midrib to or almost to the midrib (referring to leaf laminas).
Pistil: the female organs of a flower which may be a single carpel or group of carpels (adj. pistillate).
Propagation: multiplication from parent stock.
Prostrate: lying along the ground.
Pyrrolizidine: a molecule with a joined double ring structure which contains one nitrogen and seven carbon atoms.
Raceme: an inflorescence of flowers on pedicels whose growing point continues to add to the inflorescence so that the youngest flowers are nearest the apex.
Ray: (floret) outer strap-like (‘petals’) which occur in outer whorls of flower heads of the Asteraceae – also used for the branches of an (umbel) inflorescence in the Apiaceae.
Reflexed: turned abruptly backwards or downwards.
Rhachilla: the axis within the spikelet of a grass or sedge.
Rhachis: the axis or axes of a compound leaf or in. florescence.
Rhizome: an underground stem (usually horizontal) (adj. rhizomatous).
Rosette: a cluster of leaves radiating from a central crown, usually close to the ground.
Sepal: one of the (usually green) segments in the outer whorl (of 2) of the leaf-like structures of a flower (the inner segments are the petals).
Sessile: without a petiole, peduncle, pedicel or stalk, (i.e. directly attached -‘sitting’).
Sheath: (usually referring to leaves) a long, tubular stem-clasping part.
Shoot: a stem and its leaves.
Simple: (usually referring to leaves) not divided (into leaflets).
Species: a taxonomic unit which is the largest group capable of interbreeding to produce fertile offspring.
Spike: an inflorescence in the form of a raceme with sessile flowers on a simple elongated axis. The flowers may be congested or distant.
Spikelet: a small spike; the unit of a grass inflorescence usually composed of one or more florets sub tended by 2 glumes.
Spine: a hard sharp-pointed structure.
Spore: a (usually microscopic) unit of dispersal in the ferns (Pteridophytes); (in this sense equivalent to seeds in flowering plants).
Stalk: (loosely) any support organ (e.g. stem, petiole, peduncle).
Stamen: the male organ of a flower which produces pollen and usually consists of an anther and a filament (adj. staminate).
Stem: the main axis (or axes) of a plant usually bearing leaves.
Stigma: part of the female organ of a flower adapted for reception and germination of pollen.
Stolon: a horizontal stem which may take root at the nodes (adj. stoloniferous).
Style: the (usually elongated) part of the female organ (carpel(s)) of a plant; situated above the ovary and bearing the stigma.
Subspecies: a taxonomic subdivision within a species; usually geographically isolated variants.
Taxonomy: the science of the classification of organisms.
Tendril: a slender elongated thread-like organ which may cling to objects for support.
Terminal: borne at the end of (a stem etc.) (adj. terminally).
Tiller: the shoot of a grass; usually arising basally and laterally and growing erect.
Trifoliate: (strictly trifoliolate). Having three leaflets (as in clover leaves).
Truncate: terminating abruptly as if cut off.
Tuber: a swollen part (usually of an underground stem (rhizome) as in potato) (adj. tuberous).
Tubercle: a small swelling (adj. tuberculate).
Umbel: an inflorescence in which all the pedicels arise at the tip of a peduncle and the flowers lie in approximately the same horizontal plane (adj. urnbelliferous).
Valve: distinct portions into which some organs break (e.g. fruits in Brassicaceae). – also used for inner perianth segments in the Polygonaceae.
Variegated: marked with irregular patches of (usually) lighter colour; especially light patches on green leaves.
Variety: a taxonomic subdivision within a species which differs as a group in minor definable characteristics from the rest of the species, and is named according to the rules of botanical nomenclature (cf. cultivar-a variety produced artificially or selected by humans which is given a vernacular name).
Vein: discrete vascular tissue (bundles), especially in reference to leaves.
Weed: any plant growing where it is not wanted.
Whorl: a ring of three or more similar appendages.