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.

Distribution

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

Discussion

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

None.

Lower Taxa

None.

"decumbent" is not a number.

... more about "Avenula hookeri"
membranous +  and scarious +
0.25 cm2.5 mm <br />0.0025 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Gordon C. Tucker +
(Scribn.) Holub +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
flattened +
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
4 cm40 mm <br />0.04 m <br /> (20 cm200 mm <br />0.2 m <br />) +
not evident +
smooth +  and scabridulous +
folded +  and flat +
1mm;4.5mm +
spikelike +
Spike oatgrass +
not branching +
10 cm100 mm <br />0.1 m <br /> (75 cm750 mm <br />0.75 m <br />) +
not woody +
Colo. +, N.Mex. +, Minn. +, N.Dak. +, Alta. +, B.C. +, Man. +, N.W.T. +, Que. +, Sask. +, Yukon +, Mont. +, Vt. +, Wyo. +  and S.Dak. +
1/4 +  and 1/3 +
semiliquid +  and liquid +
capillary +
pistillate +  and staminate +
sometimes longer +
3 +  and 6 +
sterile +  and bisexual +
compressed +
reduced +
shorter or longer +
subtending +
unequal +
uncinate +
1 cm10 mm <br />0.01 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
1 cm10 mm <br />0.01 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
lacerate +  and acute +
0.3 cm3 mm <br />0.003 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
membranous +
inconspicuous +
0.9 cm9 mm <br />0.009 m <br /> (1.3 cm13 mm <br />0.013 m <br />) +
sclerenchymatous +
concealed +  and prominent +
2 +  and 1 +
hairy +  and glabrous +
well-developed +
2-keeled +
0.6 cm6 mm <br />0.006 m <br /> (0.875 cm8.75 mm <br />0.00875 m <br />) +
6cm +  and 11cm +
ascending +  and erect +
spikelike +
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
dry +  and fleshy +
hairy +  and glabrous +
smooth +  and scabridulous +
compressed +
1.2 cm12 mm <br />0.012 m <br /> (1.6 cm16 mm <br />0.016 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Helictotrichon hookeri +
Avenula hookeri +
species +
membranous +
0.9 cm9 mm <br />0.009 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
parallel +  and converging +
plant +  and cespitose +
aquatic +  and terrestrial +