Apera

Adans.
Treatment appears in FNA Volume 24. Treatment on page 788.

Plants annual; tufted or the culms solitary. Culms 5-120 cm, erect or geniculate, glabrous. Leaves mostly cauline; sheaths open, rounded to slightly keeled; collars glabrous, midveins continuous; auricles absent; ligules membranous, often lacerate to erose; blades flat or weakly involute, glabrous. Inflorescences terminal panicles; branches strongly ascending to divergent. Spikelets pedicellate, slightly laterally compressed, with 1 floret, rarely more, distal florets, if present, vestigial; rachillas prolonged beyond the base of the floret as a bristle, rarely terminating in a vestigial floret; disarticulation above the glumes, beneath the floret. Glumes unequal, lanceolate, scabrous on the distal 1/2, unawned; lower glumes 1-veined; upper glumes slightly shorter than to slightly longer than the florets, 3-veined; calluses blunt, glabrous or sparsely hairy; lemmas firmer than the glumes, folded to nearly terete, obscurely 5-veined, marginal veins not excurrent, apices entire, awned, awns subterminal; paleas about 3/4 as long as to equaling the lemmas, hyaline, 2-veined; lodicules 2, free, glabrous, usually toothed; anthers 3; ovaries glabrous. Caryopses shorter than the lemmas, concealed at maturity, 1.2-2 mm, ellipsoidal, slightly sulcate; hila broadly ovate, 1/5 the length of the caryopses. x = 7.

Distribution

Conn., N.J., N.Y., Wash., Del., D.C, Wis., Wyo., N.Mex., Pacific Islands (Hawaii), Ohio, Pa., B.C., Ont., Mass., Maine, Nev., Colo., Md., Calif., Oreg., Vt., Ill., Ind., Ariz., Idaho, Mont., Tex., Utah, Mo., Mich., Ky.

Discussion

Apera is genus of three species, native to Europe and western Asia. It is similar to Agrostis. It differs in its firm lemmas; paleas that are always present and equal to the lemma, or nearly so; and prolonged rachillas. In North America, two species have been introduced, growing as weeds in lawns and disturbed ground, and in grain fields.

Key

1 Anthers 0.3-0.5 mm long; panicles contracted, 0.4-3 cm wide; most branches spikelet-bearing to within 2 mm of the base Apera interrupta
1 Anthers 1-2 mm long; panicles pyramidal, 2-15 cm wide; branches naked at the base for 5 mm or more Apera spica-venti

"decumbent" is not a number.

... more about "Apera"
membranous +  and scarious +
awned +  and entire +
Kelly W. Allred +
Adans. +
1 (?) +  and 3 (?) +
straight +
subterminal +
keeled +  and rounded +
pseudopetiolate +  and branching +
intravaginal +, extravaginal +, branching +  and basal +
swelling +
not evident +
involute +  and flat +
spikelike +
hairy +  and glabrous +
not branching +
geniculate +
5 cm50 mm <br />0.05 m <br /> (120 cm1,200 mm <br />1.2 m <br />) +
not woody +
Conn. +, N.J. +, N.Y. +, Wash. +, Del. +, D.C +, Wis. +, Wyo. +, N.Mex. +, Pacific Islands (Hawaii) +, Ohio +, Pa. +, B.C. +, Ont. +, Mass. +, Maine +, Nev. +, Colo. +, Md. +, Calif. +, Oreg. +, Vt. +, Ill. +, Ind. +, Ariz. +, Idaho +, Mont. +, Tex. +, Utah +, Mo. +, Mich. +  and Ky. +
1/4 +  and 1/3 +
liquid +, soft +  and hard +
capillary +
pistillate +  and staminate +
sterile +  and bisexual +
compressed +
reduced +
shorter or longer +
subtending +
lanceolate +
unequal +
uncinate +
folded +  and nearly terete +
lacerate +
membranous +
inconspicuous +
concealed +  and prominent +
2 +  and 1 +
well-developed +
2-keeled +
spikelike +
dry +  and fleshy +
warwick1987a +
rounded +  and slightly keeled +
1 +  and 60 +
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 +
Poaceae tribe Poeae +
membranous +
slightly shorter than to slightly longer than the florets +
parallel +  and converging +
stoloniferous +  and rhizomatous +
aquatic +  and terrestrial +