Glossary of Terms A – L

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| A – L | N – Z |

Achene: a (typically small) ‘seed-like’, one-seeded fruit which does not open to release the seed.

Alkaloids: a heterogeneous group of chemicals with nitrogenous bases which occur naturally in plants. Many produce a strong physiological reaction when introduced into animals.

Allergen: a substance which produces an abnormal (and repeatable) hypersensitivity (allergy) in some individuals.

Alternate: not diametrically opposite but occurring singly at different heights; usually refers to an arrangement of leaves.

Anther: pollen-containing sac of stamen at the summit of the filament.

Apex: the growing point of a stem; the tip of a leaf.

Auricles: paired appendages often at the base of leaf blades in grasses and at the base of some other leaves.

Awn: a bristle-like appendage (common in grasses).

Axil: the upper angle between the stem (or other axis) and any organ (usually a leaf) arising from the stem (adj. axillary).

Berry: a fleshy fruit with few to many seeds derived from a single pistil.

Biennial: living for more than one but less than two (calendar) years.

Bipinnate: twice pinnately divided (usually referring to leaves).

Blade: the expanded part (lamina) of a leaf or bract; particularly of a grass leaf.

Bract: a leaf-like structure or scale often surrounding flowers or inflorescences.

Bulb: a storage organ, usually underground, consisting of a short stem and swollen leaf bases surrounded by dry leaf bases (as in onions) (adj. bulbous).

Bulbil: a small bulb.

Calyx: the sepals collectively (outer whorl) of a flower; sepals may be combined into one structure.

Capitulum: a dense cluster (inflorescence) of flowers combined into a structure which often has the appearance of a single flower (common in the Asteraceae) (pl. capitula).

Capsule: a dry fruit containing at least two seedbearing structures.

Carpel: the combined unit of the female flower parts usually consisting of stigma, style and ovary.

Compound: usually referring to leaves in which the blade is divided into separate leaflets. Also used in relation to inflorescences which are composed of several units such as spikes.

Corm: a solid part of the stem, usually underground, surrounded by dry leaf bases.

Corolla: the petals of a flower collectively.

Corymb: an inflorescence which is a raceme, but has pedicels graded in length so that the flowers are in the same horizontal plane (adj. corymbose).

Cotyledon: the first leaf or leaves of a plant emerging from a seed.

Crown: tissue at the junction of the root and stem.

Cultivar: a ‘cultivated variety’ within a species created artificially (by breeding) or selected for cultivation by humans which is given a vernacular name (cf. variety).

Cyme: a branched inflorescence in which each flower is terminal to a shoot including tile main stem (adj. cymose).

Disc: (floret) a small flower, usually tubular in shape, borne on the central part of flower heads in the Asteraceae.

Elliptical: shaped like an ellipse.

Emergent: refers to parts of aquatic plants growing above the water surface.

Entire: (of a leaf margin) smooth, without incisions or lobes.

Epicotyl: the part of the stem of a seedling between the first leaves and the cotyledons.

Exotic: from abroad.

Family: a taxonomic group of related genera.

Female: pistillate organs of a flower; or flowers which only contain (functionally) pistillate organs (style, stigma, ovary).

Floret: an individual flower, usually small, forming part of an inflorescence, as in the Poaceae and Asteraceae.

Flower: the sexual reproductive structure of higher plants.

Frond: the ‘leaf’ of a fern.

Fruit: seed-bearing structure in higher plants developed from the ovary after fertilisation.

Genus: a taxonomic group of closely-related species (pl. genera).

Glabrous: without hairs (leaf).

Gland: a structure which secretes nectar, oil or other substances (adj. glandular).

Glume: a bract (usually in pairs) at the base of a grass spikelet or in an inflorescence in the Cyperaceae.

Herb: a plant without a woody stem, usually broad leaved (i.e. not grass) (adj. herbaceous).

Herbarium: a systematically-arranged collection of dried plant specimens for botanical reference and research.

Herbicide: a chemical product having deleterious effect upon plants.

Hybrid: offspring of parents of different species.

Hypocotyl: the stem of a seedling between the cotyledons and the roots.

Inflorescence: a group of flowers arising from one main stem.

Internode: the part of a stem between two adjacent nodes.

Involucre: a whorl or several whorls of bracts (phyllaries) surrounding a flower or inflorescence.

Lamina: the expanded portion of a leaf (as in the blade of grass leaves).

Lanceolate: lance-shaped; much longer than broad, widening above the base and tapering to the apex.

Lateral: (veins) veins arising from a midvein or midrib.

Latex: a milky fluid in some plants.

Leaflet: unit of a compound leaf.

Legume: fruit pod of the family, Fabaceae (e.g. a wattle).

Lemma: the lower (outer) of two bracts enclosing other floral parts in grasses.

Ligule: membranous (or hairy) structure at the inner junction of the leaf sheath and blade of grasses (adj. ligulate).

Linear: long, narrow, straight , parallel-sided (especially most grass leaf blades).

Lobed: with convex projections.