Poa arctica ssp. arctica
Poa arctica ssp. lanata

General:
Perennial, densely to loosely tufted grass from fibrous roots and rhizomes; stems usually decumbent, 7.5-60 cm tall/long.

Leaves:
Sheaths hairless, margins open 1/2-3/4 their length; sterile shoots mainly breaking through the sheath bases; basal bladeless leaves present; blades 1-4 mm wide, flat or folded; ligules (1) 2-7 mm long, the tips blunt or rounded to sharp-pointed, entire or torn, backs smooth or slightly rough.

Flowers:
Inflorescence a lax to erect panicle, (2) 3.5-15 cm long, sparse, egg-shaped to broadly pyramidal, usually open; lowermost internodes less than 1.5 (3) cm long, the branches 1 to 5 per node, ascending or widely spreading, round, smooth or slightly to moderately rough, spikelets not crowded, longest lowermost branches 2/5-3/5 the length of the panicle; spikelets laterally compressed, 4-8 mm long, (2-) 3- to 6-flowered, sometimes with bulbils; glumes lanceolate to broadly lanceolate, keels indistinct, smooth or slightly rough near the tips, the lower ones 3-nerved, the upper usually nearly equalling to slightly exceeding the lower lemmas; rachillas smooth, hairless or sparsely minutely soft to long silky-hairy; lemmas lanceolate to broadly lanceolate, 3.5-7 mm long, the tips sharp-pointed, margins broadly translucent, surface smooth, keel and marginal nerves long silky-hairy, lateral nerves silky-hairy, mostly short silky-hairy between the nerves, lateral nerves prominent; calluses sparsely to copiously hairy; palea keels silky-hairy most of the length (rarely nearly hairless), minutely soft-hairy (or with at least a few, minute, straight hairs) between the keels; flowers bisexual (some appearing female due to aborted anthers); anthers sometimes aborted late in development or if present, 1.4-2.5 mm long.

Notes:
Two subspecies occur in BC:

1. Spikelets mostly greater than 6 mm long; lower lemmas 4.5-6 mm long; stem leaf blades often flat and more than 2 mm wide................... ssp. lanata (Scribner & Merr.) Soreng

1. Spikelets less than 6 mm long; lower lemmas 3-4.5 mm long; stem leaf blades mostly folded and less than 2 mm wide................... ssp. arctica

Source:  The Illustrated Flora of British Columbia