Yavapai County Native & Naturalized Plants

Glossary of Grass Terminology

Acuminate - gradually tapering to a sharp point

Acute - sharp pointed but less tapering than accuminate, angle less than 90 deg

Annual - a plant that usually germinates, flowers, and dies in one growing season
Attenuate- gradually narrowing to a slender apex or base

Awn - a more or less stiff bristle on the end of lemmas or glumes

Auricle - ear-like lobes at the base of a blade or the top of the sheath.

Blade - the part of the leaf above the sheath

Bract - a reduced leaf structure, includes the floret structures of glumes, lemma, and palea
Bristle - a stiff, slender appendage
Bunchgrass - a grass without stolons or rhizomes; growth habit of forming a bunch

Ciliate - fringed with hairs on the margin

Collar - the region of the outer side of the grass leaf at the junction of the blade and sheath

Convolute - rolled longitudinally
Cool Season - growth begins in early spring, stops in the summer, and may regrow in the cool months of the fall. Generally exhibit the C3 photosynthetic pathway.

Creeping - spreading just under the surface of the soil

Culm - the stem of the grass plant.

Decurrent - extending downward from the point of attachment

Decumbent - term applied to stems that lie flat and turn up at their ends

Distally - opposite point of attachment

Entire - whole with a continuous margin
Erose - irregularly notched at the apex, appearing gnawed or eroded
Flexuous - bent alternately in opposite directions; a wavy form

Floret - an individual grass flower including its 2 bracts, lemma and palea

Geniculate - bent abruptly , like a knee
Glabrous - smooth without hairs
Glaucous - covered with powdery or waxy bloom as a plum or cabbage leaf.

Glumes -pair of bracts at the base of a spikelet

Hirsute - with straight rather stiff hairs
Hispid - with rather long stiff hairs
Hyaline - colorless and translucent

Inflorescence - the flowering part of a plant
Internode - the part of a stem between 2 successive nodes

Involute - rolled inward on the upper surface
Introduced - species which have been brought into North America
Invader - undesirable range plants which invade and take over a range after the decreasers and increasers are largely gone

Lemma - the lower bract of the two bracts of a grass floret
Knotty - with a hardened mass at the base or nodes

Lacerate - appearing torn at the edge or irregularly cleft

Ligule - the membranous or hairy, usually flap-like appendage on the inside of a leaf at the junction of the sheath and blade
Membranous - thin, like a membrane
Native - species which originated in North America

Nerve - vein on glume, lemma or palea

Node - region on a stem where where leaves and branches are produced

Obtuse - blunt or rounded (apex or base), usually making an angle of more than 90 degrees

Palea - the inner of the 2 bracts of a grass floret

Pedicel - the stalk of a spikelet
Perennial - a plant living more than 1 year

Pistil - female reproductive structures of a flower

Pilose - soft-hairy

Puberulent - dimunitive of pubescent
Pubescent - clothed with soft hairs or down

Raceme - an inflorescence in which the spikelets are pedicelled on a rachis

Retrorse - directed back or downward

Rhizome - an underground stem
Rhizomatous - having rhizomes

Scabrous - roughened with stout projections

Seedhead - the flowering portion of a grass plant

Seedhead stem (Culm) - the jointed stem of a grass

Sheath - the part of a leaf that envelopes the stem
Sod-forming - a grass with stolons or rhizomes
Spike - an unbranched inflorescence in which the spikelets are sessile on a rachis
Spikelet - the unit of inflorescence in grasses consisting of 2 glumes and 1 or more florets

Sterile - without female reproductive structures
Stolon - an above ground modified reproductive stem
Stoloniferous - bearing stolons

Striate - marked with slender, longitudinal grooves or lines, appearing striped.
Strigose - with stiff, straight, appressed hairs

Tometose - covered wth matted and tangled hairs
Truncate - as though abruptly "chopped off" at the base or apex
Villous- densely hairy with long, soft hairs

Warm season - growth begins in late spring, continues through summer, and stops in early fall

  Arizona Cooperative Extension
Yavapai County
840 Rodeo Dr #C
Prescott, AZ 86305
(928) 445-6590
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Last Updated: Dec 13, 2022
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