General:
Perennial grass from fibrous roots; stems 50-150 (200) cm tall.

Leaves:
Sheaths smooth to soft-hairy; blades (5) 8-15 mm wide, flat, smooth to soft-hairy on the dorsal surfaces at least, thin, the nerves very narrow, scarcely 1/3 as broad as the intervening areas; ear-shaped lobes lacking at the leaf-bases; ligules smooth (to crisp-hairy), jagged, pale, (2) 4-8 mm long.

Flowers:
Inflorescence a large panicle, 10-35 cm long, the branches stiffly erect to mostly spreading or drooping, usually bearing only 1 or 2 (3) spikelets near the tips; spikelets closely 4- to 8- (12-) flowered, strongly compressed, tapered from near the base, 2-4 cm long; florets mostly small, closed, self-fertilizing; glumes lanceolate, keeled, the lower ones 3- or 5-nerved, 8-10 mm long, the upper ones, 5- or 7-nerved, 2-3 mm longer; lemmas smooth to more or less short-hairy, keeled on the back, (6) 7-12 mm long, shallowly bidentate, awned, the awns straight or slightly abruptly bent, (5) 7-12 (15) mm long; rachillas completely exposed to often not exposed; paleas about equalling or exceeding the lemmas; anthers (0.5) 1-3 (6) mm long.

Notes:
The treatment here follows that of Calder and Taylor (1968) who suggested that B. aleutensis was merely a depauperate form of B. sitchensis. They can be separated only on minor and overlapping differences in panicle characteristics.

Source:  The Illustrated Flora of British Columbia