Plant Terms Glossary

Accrescent – Enlarging with age.
Achene – a small dry, one seeded fruit which does not split at maturity.
Acute – ending in a sharp point.
Adventitious – In an unusual or unexpected place.
Aerial –In the air.
Allelopathic substances – chemical compounds produced by plants that affect the interactions between different plants, including microorganisms.
Alternate – Singly along a stem; one leaf or bud at node.
Anthesis – Flowering; when pollination takes place.
Apex – The tip.
Appressed – Pressed flatly against the surface.
Ascending – Growing upward in a upturned position.
Auricle – Having small ear-shaped lobe or appendage.
Awn – The angle between a leaf and stem.
Axillary – Between the petiole or branch and the stem.
Biennial – A plant which lives two years.
Bract – A small leaf-like structure below a flower.
Calyx – The outer parts of a flower composed of usually leaf-like parts called sepals.
Capillary – Hairlike, slender and thread-like.
Caudex – The main stem of a plant at or just below the ground surface.
Chlorophyll – The green coloring matter of plants.
Clasping – Blade of the leaf extending beyond and surrounding the stem.
Clavate – Club-shaped.
Conical – Cone-shaped.
Cordate – Heart-shaped.
Corolla – The petals of a flower surrounding the stamens and pistil.
Crenate – With rounded teeth; scalloped.
Cylindrical – Having the form or shape of a cylinder.
Cyme – A short and broad, somewhat flat-topped flower cluster in which the central flower blooms first.
Deciduous – Leaves falling at maturity or the end of a growing season.
Decompound – Divided into compound divisions; repeatly compound.
Decumbant – Lying on the ground at the base, but rising at the tip.
Depauperate – Stunted.
Dimorphic – Occuring in two distinct forms.
Disk flower – a tubular flower in members of the sunflower family.
Elliptic – Oval or oblong with rounded ends and more than twice as long as broad.
Entire – Leaf margins that are not cut or toothed.
Filament – Anther-bearing stalk of a stamen; thread.
Floret – One of the closely clustered small flowers that make up the flower head of a composite flower-  Grass flower consisting of a lemma, palea, stamens, and/or pistil.
Frond – The leaf of a fern.
Glabrous – Smooth; without hairs.
Glume – Bract at the base of a grass spikelet.
Indehiscent – Not opening at maturity.
Inflorescence – The flowering part of the plant.
Involucre – A circle of bracts under a flower cluster.
Keel – A ridge; the two united front petals of a flower.
Lanceolate – Lance-shaped.
Leaflet – One small blade of a compound leaf.
Ligule – A thin, membranous outgrowth or fringe of hairs from the base of the blade of
most grasses.
Linear – Long and narrow with parallel sides.
Lobed – Cut into shallow segments.
Membranous – Thin and transparent.
Midrib – Central vein of a leaf.
Multifloreated – Many flowered.
Obicualar – Circular.
Oblanceolate – Lance-shaped, tapering at both ends with the broudest part at tip end.
Obovoid – Egg-shaped with broader part at top.
Opposite – Arranged on the same node at the opposite side of the stem.
Orbicular – Circular.
Ovary – The seed-bearing part of the pistil.
Ovate – Egg-shaped with broader part at base.
Palmate – Spreading like the fingers from the palm.
Panicle – Loose, irregularly compound flowering part of plant with flowers borne on individual stalks.   
Pappus – Bristles, scales, awns or short crown at tip of achene in flowers of sunflower family.
Pedicel – Stalk of a single flower.
Peduncle – Stalk of a flower cluster or individual solitary flower.
Perennial -  A plant living more that two years.
Perfect flower – having both stamens and pistils in the same flower.
Petiole – Stem or stalk of a leaf.
Phloem – Food transporting tissue of a plant.
Pinnate – Arising from several different points along the sides of an axis.
Pinnatifid – Pinnately cleft.
Pistillate – Bearing pistils, but no stamen.
Prostrate – Lying against the ground.
Pubescent – covered with hairs.
Raceme – Arrangement of flowers along a xstem on individual stalks about equal in length.
Rachis – The main stem bearing flowers or leaves.
Ray Flower – marginal petal-like flowers of some composites.
Receptacle – The part of the stem to which the flower is attached.
Reflexed – Turned abruptly downward or backward.
Reticulate – Net-like
Rhizomatous – Having rhizomes.
Rhyzome – Underground stem, usually lateral, sending out shoots above ground and roots below.
Rossete – Compact cluster of leaves arranged in an often basal circle.
Rugose – Wrinkled.
Scale – Thin, dry membrane, usually foliar.
Sepal – One division of the calyx.
Serrate – Saw-toothed, with sharp, forward-pointing teeth.
Sessile – Without stalk.
Sheath – Lower part of the leaf which surrounds the stem.
Silicle – A short silique, almost equally as long as wide.
Silique – Elongated capsule with a septum separating in two halves.
Simple Leaves – Unbranched, not compound.
Spatulate – Spoon-shaped, narrow at base and wide at apex.
Spike – A usually long inflorescence with sessile flowers.
Spikelet – Small or secondary spike; flower cluster in grasses consisting of usually 2 glumes, and one or more florets.
Spinose – Full of spines.
Stamen – The pollen-bearing organ of a flowering plant.
Staminate – Having stamens, but no pistil.
Stellate – Star-shaped.
Stigma – Part of the pistil that receives the pollen.
Stolon – A horizontal stem which roots at the nodes.
Striate – Marked with parallel lines or ridges.
Subtended – Underneath, directly below and close to.
Succulent – Fleshy.
Terete – Circular in cross-section.
Toothed – Sawteeth-like projections on the margins of the blade.
Tuberous – Like a tuber or producing tubers.
Tufted – In compact clusters.
Umbel – A flat or rounded flower cluster in which the stalks radiate from the same point, like the ribs of an umbrella.
Utricle – Small, inflated, 1-seeded, usually indehiscent fruit.
Veins – Ribs of a leaf; vascular bundles on a leaf.
Wing – A thin, membranous extension of a leaf blade.

By: Alfred Downs, 5/2004. HOME    Weed ID