Avenula

(Dumort.) Dumort.
Treatment appears in FNA Volume 24. Treatment on page 698.
 TaxonIllustrator 
FNA24 P269 Avenula pg 699.jpegAvenula pubescens
Avenula hookeri
Linda Ann Vorobik
Hana Pazdírková
Linda Ann Vorobik
Hana Pazdírková

Plants perennial; cespitose, sometimes stoloniferous. Culms 10-110 cm. Sheaths usually open, sometimes closed for most of their length; auricles absent; ligules membranous, acute to truncate; blades flat or folded, adaxial surfaces unribbed, with a furrow on either side of the midveins, margins sclerenchymatous. Inflorescences reduced panicles, many branches (all branches in depauperate specimens) with a single spikelet. Spikelets with 2-7 florets; rachillas glabrous on the side adjacent to the paleas, hairy elsewhere; disarticulation above the glumes, beneath the florets. Glumes as long as or longer than the adjacent lemmas, 1-3-veined, unawned; calluses acute; lemmas 5-7-veined, obtuse, bifid, awned from about midlength, awns geniculate, flattened or terete and twisted below the bend; paleas with lateral wings less than 1/2 as wide as the intercostal region, apices shallowly bifid; lodicules 2, entire, unlobed; anthers 3. Caryopses more than twice as long as the hila, shorter than the lemmas, concealed at maturity; endosperm liquid or semiliquid, x = 7.

Distribution

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

Discussion

Avenula is a genus of approximately 30 species, most of which are European. One species is native to the Flora region, and one has been introduced. The genus is frequently included in Helictotrichon, from which it differs in having acute cauline ligules, unribbed leaves, rachillas glabrous on one side, unlobed lodicules, short hila, liquid to semi-liquid endosperm, and no sclerenchyma ring in its roots.

Key

1 Sheaths closed for less than 1/3 their length, sheaths and blades smooth to scabridulous; panicles 4-13 cm long, usually 0.8-2.5 cm wide; awns 10-17 mm long, flattened below the bend Avenula hookeri
1 Sheaths closed to near the top, sheaths and blades usually pubescent; panicles 6-20 cm long, 2-6 cm wide; awns 12-26 mm long, terete below the bend Avenula pubescens

"decumbent" is not a number.

... more about "Avenula"
membranous +  and scarious +
Gordon C. Tucker +
(Dumort.) Dumort. +
1 (?) +  and 3 (?) +
straight +
basal +  and terminal +
terete +, flattened +  and geniculate +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
not evident +
folded +  and flat +
spikelike +
hairy +  and glabrous +
not branching +
ascending +  and erect +
10 cm100 mm <br />0.1 m <br /> (110 cm1,100 mm <br />1.1 m <br />) +
not woody +
N.J. +, Minn. +, Mass. +, N.Mex. +, Del. +, N.Dak. +, Mont. +, S.Dak. +, Vt. +, Colo. +, Alta. +, B.C. +, Man. +, N.W.T. +, Ont. +, Que. +, Sask. +, Yukon +, Wyo. +  and Conn. +
1/4 +  and 1/3 +
semiliquid +  and liquid +
capillary +
pistillate +  and staminate +
sometimes longer +
2 +  and 7 +
sterile +  and bisexual +
compressed +
reduced +
shorter or longer +
subtending +
unequal +
uncinate +
awned +  and bifid +
acute +  and truncate +
membranous +
inconspicuous +
sclerenchymatous +
concealed +  and prominent +
2 +  and 1 +
hairy +  and glabrous +
well-developed +
2-keeled +
spikelike +
dry +  and fleshy +
hairy +  and glabrous +
dixon1991a +, gervais1973a +  and holub1963a +
compressed +
0.07 cm0.7 mm <br />7.0e-4 m <br /> (5 cm50 mm <br />0.05 m <br />) +
1 (?) +  and 3 (?) +
simple +  and compound +
2 (?) +  and 3 (?) +
Gramineae +
Avenula +
Poaceae tribe Poeae +
membranous +
parallel +  and converging +
plant +  and cespitose +
aquatic +  and terrestrial +