GLOSSARY OF BOTANICAL AND TECHNICAL TERMS

The following is a list of terms given throughout The Plants Directory: Volume 1, North-east NSW, and their meanings.

The letters given above will guide you to that part of the list to hasten your search. Use the Glossary link at the top of this page when coming to this window from any other, then select the required letter.


Alphabetical list.

  • Achene - an indehiscent fruit in which the seed is not fused to the fruit wall. The 'seed' of the daisies is an example.
  • Adventitious - growing from an unusual part of the plant, like roots from midway along a stem, or new plants from along a stem instead of at the base, or on an inflorescence.
  • Appendix -the sterile upper portion of an organ, such as the uppermost part of an anther or the upper, sterile portion of an Araceae (Arum-lily family) inflorescence.
  • Aril (arillate) - a fleshy or membranous appendage on the seed, which may be at one or both ends (as in most wattles) or may surround the seed (as in many Sapindaceae).
  • Articles - a part of an organ that seperates easily from the rest of the organ, such as a lomentum or the segments of the branchlets between the teeth whorls in Casuarinaceae.
  • Auriculate - 'ear-like' - when describing leaves this generally means that the basal margin is extended into two short, rounded lobes.
  • Australasia - The region including Australia, New Guinea, New Caledonia, New Zealand and the nearer parts of Polynesia.
  • Awn - a bristle-like structure on the end or back of an organ, such as the awned lemmas of many grasses.
  • Axil (axillary) - the upper-side of the angle formed when one part of a plant joins onto another. Mostly used in the sense of the upper angle formed between the stem and the leaf petiole.
  • Axis - the main stem of an organ, such as the stem or an inflorescence or the rachis of a compound leaf.
    B
  • Barbellate - with minute barbs.
  • Bipinnate - compound leaves in which the leaflets are borne on an axis that has branched of the main axis. There are two levels of branching within the leaf structure.
  • Blade (of leaves) - The lamina or flattened part of the leaf.
  • Botryoids - simple inflorescences in which the axis ends in a flower bud.
  • Bract (bracteate) - a modified and much-reduced leaf that occurs mainly on inflorescences, and may be on the peduncle (stem) or below each flower.
  • Bracteole - a reduced bract-like structure on the flower pedicel or at the base of the calyx.
    C
  • Calyptra - The cap over the bud of a eucalypt flower composed of the fused petals and sepals.
  • Calyx - the lower whorl of flower parts, also known as the sepals.
  • Capitate - in a dense or head-like cluster (capitulum) or shaped like a head.
  • Capitulum (capitula) - a densely-arranged cluster of sessile flowers, mainly on a flattened receptacle, as in the daisies (Asteraceae).
  • Caryopsis - a dry and indehiscent 1-seeded fruit in which the seed is fused to the fall of the fruit. The 'seed' or grain of a grass is a caryopsis.
  • Cataphyll - a scale-like leaf, similar to a bract, on a vegetative part of the plant (such as on a rhizome), often with a sheathing base, and in some cases with the leaf reduced to a small awn (as in Juncus).
  • Cauliflorous - bearing flowers on the trunk or other main stem.
  • Chasmogamous - flowers that are pollinated while they are open. (Compare to cleistogamous.)
  • Cladode - a flattened or otherwise modified, green stem that acts as a photosynthetic surface, mainly leafless when mature.
  • Claw - The narrower, basal part of a structure, such as the slender basal part of a petal or involucral bract.
  • Cleistogamous -flowers that are pollinated before they open, or which do not open and are still pollinated. (Compare to chasmogamous.)
  • Coccus (plural cocci) - a single unit of a of schizocarpic fruit formed from one carpel in the flower which may or may not be dehiscent, or a dehiscent, often flattened capsule-like structure.
  • Column - a)the structure at the centre of an orchid flower formed of the fused style and stamen filaments; b) the central, column-shaped structure in a flower or fruiting perianth of Malvaceae, Asclepiadaceae and Geraniaceae, among others, which is often formed from fusion of the stamens and style.
  • Conflorescence - the inflorescence in which the main stem is quite different to the sections bearing the flowers. Better-known examples include the 'inflorescences' of many grevilleas.
  • Corm - a form of underground storage and perennation organ in which the stem becomes contracted and starchy. Examples include the bulbs of many Iris family plants like gladioli and freesias.
  • Culm - the aerial stem that bears the flowers and fruit in monocots, such as the stem of grasses, sedges and rushes.
  • Crozier - Shaped in such a fashion that it uncoils as it develops, such as the fronds of many ferns.
  • Cyathium - the inflorescence unit in which the flowers are unisexual, much reduced, and in a cluster surrounded by bracts. This style is found in many Euphorbia species.
  • Cyme - an inflorescence in which there are one to many lateral branches, each ending in a flower, and the branching is in a repeated unit throughout.
    D
  • Decurrent - the structure is extended downwards below the point of insertion, such as a petiole forming a ridge along the stem below where it joins.
  • Decussate - Paired, with alternate pairs at right angles to each other.
  • Dehisce (dehiscent) - a structure that opens at maturity to release the contents.
  • Diad - a unit in which the organs are borne in equal pairs. In this sense it refers to the inflorescence of some mistletoes in which there are a pairs of similar flowers.
  • Dichasium - a cyme in which the inflorescence has two branches at each node (as well as the flower stem).
  • Digitate - finger-like, or otherwise resembling the fingers of a hand, such as a palmate leaf in which the leaflets all arise from a single point.
  • Dioecious - having the two sexes on seperate plants.
  • Disarticulating - breaking into a number of discrete articles.
  • Distichous - '2-ranked', or having alternate leaves on either side of a stem.
  • Drupe (Drupaceous) - an indehiscent, succulent or fleshy fruit in which there are three layers of tissue. The outer skin (epicarp), the fleshy layer (mesocarp) and a hard inner layer (pericarp) surrounding a single or multiple seed. An example is a peach, in which the skin is the epicarp, the flesh the mesocarp, and the stone is the pericarp.
    E
  • Endocarp - the innermost layer of the pericarp, which is often membranous.
  • Epicarp - the outermost layer or a drupeaceous fruit.
  • Equitant - when organs (such as leaves) are presented in a single plane. (The proper use of this term has the uppermost surfaces of leaves fused together and hidden except at the base where they surround the base of the next uppermost leaf.)
  • Exocarp - the combined epicarp and mesocarp of a fruit.
    F
  • Fertile - bearing fruit or seeds, such as the bisexual florets of grasses which will produce a caryopsis compared tot he sterile (generally male) florets.
  • Floral parts - the flower is composed of a number of whorls of similar structures. In the simplest form there is, from the base, the pedicel, then the calyx (sepals), corolla (petals), androecium (stamens and anthers) and the gynoecium (ovary, style and stigma).
  • Floret - a small flower, as in daisies, or a grass flower and the lemmas and palea that are with it.
  • Foliose - leaf-like.
  • Fusiform - 'cigar-shaped', elongate-oblong with rounded ends.
    G
  • Galea - the 'hood' formed in Pterostylis flowers from the dorsal sepal fused to the petals.
  • Geniculate - knee-shaped, bent at right angles.
  • Glabrous - without any hairs.
  • Glume - a bract on the inflorescence of some monocots, mainly at the base of the spikelet.
  • Graminoid - a grass-like plant.
    H
  • Helical (helically) - arranged in a spiral.
  • Herbaceous - herb-like, or soft and not woody.
  • Hyaline - translucent or glassy in appearance.
  • Hypanthium - cup-like structure above the base (often above the top) of an ovary. It bears the bases of the perianth segments and the stamens on the rim.
    I
  • Imbricate - folded between or enclosed within the same organ, such as the leaves of an nion, or the presentation of petals in some buds.
  • Inflorescence - the all-encompassing term for the structure bearing the flowers of the plant.
  • Indusium - a covering structure over the sorus of ferns, or the pollen-cup of members of the Goodeniaceae
  • Involucre - whorl(s) of bracts surrounding a flower or an inflorescence, such as the bracts surrounding a daisy flower.
  • Irritable - responding to touch, such as the mobile, hinged labellum of some orchids (Caleana and Pterostylis in particular) or the glandular hairs on Drosera species.
    L
  • Labellum - the lip, or modified petal of the orchid flower, developed as a landing pad or attractant for pollinating insects.
  • Lamina - the flattened, photosynthetic part of a leaf.
  • Lemma - the bract(s) closest to the flower(s) on a grass spikelet.
  • Lerp - the excreted product of some insects (Psillids mainly) which is able to be used as a sweet food source, although some starch is present and the whole lot will not dissolve in the mouth.
  • Lomentum - a particular legume structure in which the flattened pod disarticulates into 1-seeded articles for dispersal.
    M
  • Mallee - a growth form of some Eucalyptus species in which there are a number of slender stems ('whipsticks') arising in a cluster from a woody underground organ (the lignotuber). Some species may show mallee and typical, single-stemmed growth forms depending upon the age and time since fire and disturbance.
  • Manna - a sweet exudate produced in some plants after injury by insects. It is not produced from the insect, a product then known as lerp.
  • Mericarp - a single unit of a of schizocarpic fruit formed from one carpel in the flower which may or may not be dehiscent
  • Mesocarp - the often fleshy or sometimes succulent middle layer of a drupe (between the epicarp on the outside and the endocarp around the seed).
  • Monochasia (monochasial) - a Cyme with the inflorescence extended by only a single branch at each node (compare to Dichasium).
  • Monoecious - having unisexual flowers, yet both male and female are borne on the same plant (on a single inflorescence or separate inflorescences).
  • Mycorrhiza - a relationship between a fungus and a higher plant in which there is some nutrient exchange from the fungus to the plant.
    O
  • Ornate - ornamented or sculptured.
    P
  • Panicle - a type of inflorescence in which there are a number of levels (2 to many) of branching between the stem and the flowers.
  • Pappus - the hairs or bristles on the apex (top) of some small hard fruit (achenes), such as in most of the members of the Asteraceae.
  • Pedicel - the stem supporting a flower that is between the base of the flower and the rachis in racemes and some solitary flowers.
  • Peduncle (pedunculate) - the stem supporting a solitary flower or an inflorescence between the first branch (or base of the lowest flower) and the point of origin on the main stem.
  • Peltate - having the stem (usually a petiole) attached in the middle on the reverse (back) side.
  • Petiole - the stem that supports a leaf blade
  • Petiolule - The stem (between the rachis and blade) that supports a leaflet in a compound leaf.
  • Phyllode - A leaf-like structure that is actually a flattened or otherwise modified, photosynthetic rachis or petiole of a leaf that lacks a blade. Most abundant in Acacia.
  • Plicate - folded lengthwise - often several times. Also sometimes referred to as pleated.
  • Pseudobulb - the swollen, modified stem of some orchids which acts as a water and nutrient storage organ.
  • Pyrene - the endocarp and enclosed seed of a drupaceous fruit.
    R
  • Raceme - an inflorescence in which the flowers are borne on a single, unbranched stem (the rachis), with the pedicel of the flower attached directly to the rachis.
  • Rachilla - the secondary branches (stems) of a bipinnate (or more compound) leaf.
  • Rachis - the 'stem' of an inflorescence or of a compound leaf, including the branches of either, which provides support to the flowers or leaflets.
  • Ramiflorous - bearing inflorescence or flowers on the branches along a section closer to the main stem (trunk) than the leaves.
  • Resupinate - rotated so that the lowest parts are presented at the top. Mostly refers to the flowers of most orchids, where the pedicel twists during development to present the uppermost petal at a lower position (as the labellum).
  • Rhizome - an underground stem which is generally extending horizontally and is often branched.
  • Rhizomatous - having a rhizome.
    S
  • Samara - an achene in which one side of the fruit is drawn out and formed into a wing.
  • Scaberulous - finely rough or coarse to the touch.
  • Scabrous - rough to the touch, like sandpaper or the texture of rubbing sand between the fingers. When finer in the roughness it is known as scaberulous.
  • Scape - the lower part of the inflorescence, mainly below any branches and not bearing flowers.
  • Scorpioid - shaped in an uncoiling fashion, such as the shape of a crozier or scorpion's tail.
  • Septate - having septae in the structure, generally either a leaf, stem or culm.
  • Septum (septae) - an internal dividing wall.
  • Sessile - (of a leaf or flower) attached directly to the supporting stem. Sessile flowers lack a pedicel, and sessile leaves lack a petiole.
  • Simple (of leaves) - composed of a single blade, generally without lobes or if lobed, these lobes not distinctly separate from the main body of the leaf blade (compare to compound)
  • Spicate - like a spike.
  • Spicule - a small, hard structure, generally formed of siliceous material or calcite.
  • Spike - a spike has the flower calyx (or similar) attached directly to the rachis.
  • Spikelet - the complex flowering structure in grasses and some other related groups.
  • Sterile - unable to produce fruit, such as the male florets of grasses, which produce pollen but will not produce a caryopsis.
  • Stipe - a stem-like section of an organ, such as a slender, stem-like part of a fruit.
  • Stipels - Stipules for the leaflets of a compound leaf.
  • Stipules - bract-like structures at the junction of a leaf petiole and the stem, having a variety of forms.
  • Stone - term used here to describe the central, bony or hard endocarp of a drupe. In a peach it is known as a 'stone' and that use is continued here.
  • Sulcate - of a leaf, having distinct grooves on opposite sides.
    T
  • Tepal - the term used to describe a petal or sepal when these are similar to each other.
  • Tetraquetrous - 4-angled or square (mostly with hollow faces) in cross section.
  • Thyrse - an inflorescence in which there is a growth point at the apex.
  • Triad - a group of three similar units. Mainly used in this sense to mean a cluster of three flowers, as of mistletoes
  • Trigonous - having three angles, but often these not sharply defined (then termed triquetrous).
  • Triquetrous - with three equal sides, being triangular in cross-section, and with the angles sharply defined (if rounded, it is termed trigonous).
  • Turbinate - top-shaped, see also obconical.
    U
  • Umbel - an inflorescence in which the flower pedicels appear to originate from a single point.
  • Umbellaster - the inflorescence unit in eucalypts, with few to many slowers originating in a condensed umbel on a common peduncle. Essentially synonymous with umbel.
  • Utricle - a membranous or firm covering, surrounding the ovary or fruit of some grasses (Coix in particular) and Cyperaceae.
    V
  • Vesicles - bladder-like sacs or cavities filled with gas or liquid.
  • Viviparous (of fruit and seeds) - Shooting while still attached to the parent.
    W
  • Whorl - The term used to describe the having a number of the same part arising from the same place. May refer to leaves coming from a stem, or in the case of flowers, the sepals and petals.

    mail to orkology@key.net.au mail to orkology@key.net.au   © 1998