E-Flora BC: Electronic Atlas of the Flora of British Columbia

General:
Perennial, tufted grass from fibrous roots, some of the shoots non-flowering; stems 20-100 cm tall.

Leaves:
Sheaths smooth to rough-hairy; blades 4-15 cm long, 2-8 mm wide, flat; ligules 2.5-4 mm long, rough-hairy outside.

Flowers:
Inflorescence spikelike, dense, narrowly egg-shaped or lanceolate, occasionally interrupted near the base, 4.5-18 cm long, the branches ascending or appressed, barely visible, densely covered with spikelets to the base; spikelets numerous, crowded; glumes 1.5-3.5 mm long, pointed or narrowly tapering to fine points, the surfaces smooth or rough-hairy, especially on the keels; lemmas 1.2-2.2 mm long, awnless or some awned from above the middle on the back, the awns to 3.5 mm long, straight or bent; calluses sparsely to abundantly hairy, the hairs to 0.3 mm long; rachillas not prolonged; paleas variable, absent or if present, only as a minute membrane to 0.5 mm long; anthers 0.3-0.6 mm long.

Notes:
A. exarata exhibits marked variation. Awned and awnless spikelets may occur on separate plants or in the same inflorescence. Plants also vary greatly in total height and size and colour of the inflorescence. For these reasons, several varieties have been proposed.