Flora of North America species comparison

4-60 cm, outer culms of a tuft decumbent, sometimes geniculate, branched at the lower nodes.

15-75 cm, erect or decumbent, sometimes branched basally, sometimes branched aerially;

nodes 3-6;

internodes glabrous or sparsely to densely pubescent with papillose-based hairs.

basal or mainly cauline;

sheaths mostly glabrous, finely scabrous, or pubescent, pilose near the ligules;

ligules 0.2-0.5 mm, of hairs;

blades 1-30 cm long, 1-2.5 mm wide, flat to involute, papillose-based hairs often present on both surfaces, usually present on the bases of the margins.

2.5-10.5 cm, with (1)4-15 branches;

branches 5-45 mm, deciduous, densely pubescent (at least basally), with 2-10 spikelets per branch, axes extending 2-10 mm beyond the base of the terminal spikelets, apices entire;

disarticulation at the base of the branches, the break forming a sharp tip.

usually with 0.7-18 cm rachises bearing 1-6 branches, the branches sometimes digitate;

branches 10-40 mm, persistent, straight, with 20-50 spikelets, axes extending 5-10 mm beyond base of the terminal spikelets;

disarticulation above the glumes.

appressed.

pectinate, green to dark purple, with 1 bisexual floret and 1-2 rudimentary florets.

acuminate or awn-tipped;

lower glumes 1.4-3.5 mm;

upper glumes 3-6 mm, midveins with papillose-based hairs;

lowest lemmas 2-4.5 mm, pubescent, 1-3-awned, central (or only) awns 0.2-2.5 mm, not flanked by membranous lobes, lateral lobes acuminate, unawned or with awns no longer than the central awn;

lower paleas ovate, unawned;

anthers 2-3.4 mm, cream or yellow;

rachilla segments subtending second florets glabrous or pubescent, sometimes with a distal tuft of hairs;

second lemmas 0.5-2 mm, bilobed, 3-awned, awns 2-4(6) mm;

third lemmas, if present, minute, membranous scales, glabrous.

2.5-3 mm.

1.5-2.6 mm.

0.2-0.5 mm, membranous, lacerate or ciliate;

blades 2-5(9) cm long, 0.7-2 mm wide, flat or folded, adaxial surfaces sometimes with papillose-based hairs, margins usually with papillose-based hairs near the ligules.

spikelet on each branch with 1 floret;

lower glumes 1.5-3.5 mm, glabrous, narrow to subulate;

upper glumes 5.5-6.2 mm, densely pubescent, at least on the basal 1/2;

lemmas 5.8-6 mm, acuminate, unawned;

lowest paleas almost as long as the lemmas, bifid, glabrous;

rachillas prolonged beyond the florets for about 0.5 mm.

spikelets with 1 bisexual and 1 rudimentary floret, glumes unequal, glabrous, minutely scabrous on the keels; narrowly acute or acuminate;

lower glumes 1.5-2 mm;

upper glumes 5-6 mm, glabrous or sparsely pubescent basally, often divergent;

lowest lemmas 6-8 mm, veins pubescent, lateral veins excurrent as short (to 1 mm) awns, acuminate, midvein extended into a setaceous tip or a short awn;

lowest paleas 5-7 mm, bifid, veins often excurrent as short awns;

anthers about 2.5 mm, yellow or yellow and red;

distal florets reduced to a pubescent, 3-awned, awn column, awns 2-7 mm, exserted.

= 40.

= 20, 40, 50, 60; numerous dysploid numbers also reported.