Plants rhizomatous. Culms 25-90 cm tall, erect; nodes 2-4(6). Ligules 0.4-4 mm, truncate to subacute, entire or lacerate; blades 4-18 cm long, 1-2.5 mm wide, flat. Panicles 5-15 cm long, 2-10 cm wide, lanceloid to ovoid, often drooping, sparsely branched;lowest node with 1-(5) branches; branches usually scabridulous, sometimes smooth, erect to ascending or spreading, spikelets usually restricted to the distal 1/2; lower branches 3-6 cm; pedicels 2-10 mm. Spikelets usually purplish bronse, sometimes greenish purple; rachilla prolongations 0.5-1.9 mm, bristelike, distal hairs shorter than 0.3 mm. Glumes usually subequal, 2.3-4.3 mm, veins sparsely scabridulous distally, apices acute to acuminate, sometimes apiculate; lower glumes usually 3-veined, lateral veins faint; calluses glabrous or sparsely hairy, hairs to 0.1 mm long; lemmas 2.5-3.5 mm long, smooth, opaque, 3(5)-veined, veins usually obscure, apices acute, entire or the veins excurrent to about 0.3 mm, unawned; paleas 2-3 mm,; anthers 3, 0.8-1.3 mm. Caryopses 1.2-1.5 mm; endosperm solid. 2n = 14.
Podagrostis aequivalvis grows along lake, bog, and stream margins, and in forest fens. It is common in the coastal regions of Alaska and British Columbia, and occurs less frequently inland, as well as to about 1500 m in the Cascade Mountains of Washington. The record from Oregon was based on a misidentified specimen of P. thurberiana. .