NASSELLA Desv. Needlegrass
Plants hermaphroditic, caespitose, perennial. Culms ascending (rarely erect), nodes glabrous; internodes hollow, terete.
Leaves basal, not distinctly distichous; sheaths terete, margins open; auricles absent; ligules membranous; blades flat or
involute, linear (narrow), stiff or lax (pubescent). Cleistogamous spikelets when present in sheaths of basal leaves.
Panicles open, or contracted; primary branches ascending (drooping with age), terminating in a spikelet. Spikelets
solitary, laterally compressed (immature terete), disarticulation above the glumes, awned, pedicellate; florets 1,
reduced floret absent, callus hairy (pungent), rachilla not extended beyond upper floret; glumes 2 (acute to acuminate),
equal, 3-veined, longer than floret, glabrous, awnless to short awned; lemmas 3-veined (inconspicuous), indurate,
margins strongly overlapping, glabrous or hairy, apex entire, fused, awned; awn apical, geniculate and twisted,
scabrous; paleas veinless (short), less than one-third lemma length, flat, awnless, glabrous. Stamens 3; anthers
yellow. Caryopses laterally compressed, oblong. Base chromosome number x=7.
A small genus of about 15 species from temperate regions. These species are adventive and adapted to