Flora of North America species comparison

15-35 cm, stiffly erect, all but the upper 2-4 internodes very short;

nodes glabrous or with weak, reflexed hairs;

internodes purplish-gray, sparsely pubescent;

fall phase developing early, forming erect branches from the lower or midculm nodes, each branch terminating in a partially included panicle of 8-16 spikelets, no sterile shoots formed.

20-100 cm, decumbent to erect, sometimes geniculate;

nodes usually glabrous, sometimes sparsely pilose or densely bearded with retrorse hairs;

internodes often purplish or olive green, lowest internodes usually glabrous, varying to sparsely pubescent;

fall phase usually branching freely, especially from the nodes above the middle, ultimately forming dense, reclining fascicles of divergent branchlets with numerous reduced, thin, often involute blades, secondary panicles often reduced, with few spikelets.

usually 3;

sheaths hirsute, hairs papillose-based;

ligules 0.5-1 mm;

blades 4-8 cm long, 2-5 mm wide, all alike, stiffly erect, green to grayish-green, flat, not plicate, sparsely pilose.

4-7;

sheaths usually shorter than the internodes, usually glabrous, occasionally the lower sheaths sparsely to densely soft-pubescent, sheaths of the uppermost leaves sometimes with whitish glandular spots between the prominent veins, margins of all sheaths glabrous or ciliate;

ligules absent or shorter than 1 mm, of hairs;

blades 3.5-14 cm long, 5-14 mm wide, usually thin, distant, spreading to reflexed or (occasionally) ascending, yellow-green to purplish, usually glabrous on both surfaces or (at least the lower blades) more or less densely and softly pubescent, bases constricted (in narrow-bladed subspecies) or narrowly subcordate (in wide-bladed subspecies), margins glabrous or ciliate basally, glabrous distally, blades of the flag leaves usually spreading.

2.4-3.2 mm long, 0.7-1.2 mm wide, ellipsoid to obovoid, often reddish throughout, short-pubescent.

1.5-2.7 mm, usually ellipsoid or obovoid, green or purplish (at least at the base), glabrous or (less commonly) sparsely pubescent or puberulent, often prominently veined, obtuse to acute to beaked.

0.7-1.2 mm, triangular;

upper glumes and lower lemmas about equaling the upper florets;

upper florets 1.9-2.5 mm, ellipsoid, pointed.

usually less than 1/3 as long as the spikelets, obtuse to acute;

upper glumes usually slightly shorter than or as long as the lower lemmas and upper florets (occasionally extending beyond the floret);

lower florets sterile;

upper florets 1.3-2 mm long, usually less than 1 mm wide, ellipsoid, subacute to obtuse.

rosettes poorly differentiated;

sheaths glabrous;

blades 2-4 cm, narrow, similar to those of the lower cauline leaves, ascending to spreading.

rosettes well-differentiated;

blades ovate to lanceolate.

panicles 3-5 cm long, 2-4 cm wide, ovoid, open, shortly exserted, with 12-32 spikelets;

branches short, stiff, spreading;

pedicels mostly 4-8 mm, spreading.

panicles 3-12 cm, long-exserted, usually with many spikelets;

branches wiry, mostly spreading or ascending, usually glabrous, sometimes scabridulous.

= 18.