Avenula hookeri

(Scribn.) Holub
Common names: Spike oatgrass
Synonyms: Helictotrichon hookeri
Treatment appears in FNA Volume 24. Treatment on page 698.

Plants cespitose, not stoloniferous. Culms 10-75 cm, erect. Sheaths closed for less than 1/3 their length, smooth to scabridulous; ligules 3-7 mm, acute, usually lacerate; blades usually 4-20 cm long, 1-4.5 mm wide, smooth to scabridulous, margins cartilaginous and whitish. Panicles (4)6-11(13) cm long, usually 0.8-2.5 cm wide, erect or ascending; branches 10-25 mm, usually straight, stiff, usually with 1-2 spikelets. Spikelets 12-16 mm, with 3-6 florets; rachilla internodes usually 1.5-2.5 mm, hairs 0.2-1.5 mm. Glumes thin, acute; lower glumes 9-13 mm, 3-veined; upper glumes 9-14 mm, 3-5-veined; calluses bearded, hairs usually shorter than 1 mm; lemmas 10-12 mm, awned, awns 10-17 mm, flattened below the bend; paleas 6-8.75 mm; anthers 2.5-5 mm. 2n = 14.


Colo., N.Mex., Minn., N.Dak., Alta., B.C., Man., N.W.T., Que., Sask., Yukon, Mont., Vt., Wyo., S.Dak.


Avenula hookeri grows on mesic to dry, open prairie slopes, hillsides, forest openings, and meadows, in montane to subalpine zones, from the Yukon and Northwest Territories to northern New Mexico.

Selected References


Lower Taxa