Flora of North America species comparison

10-60(70) cm tall, 0.5-1.8 mm thick, erect or the bases decumbent, terete or weakly compressed;

nodes terete, 0-2 exserted.

5-80 cm, usually slender, mostly erect or ascending, several to many arising together;

nodes terete or slightly compressed, (0)1-2(3) exserted, top node usually at 1/3 – 3/5 the culm length.

closed for 1/4-3/4 their length, terete, smooth or scabrous, glabrous, bases of basal sheaths glabrous, distal sheath lengths 1.6-10 times blade lengths;

collars smooth or scabrous, glabrous;

ligules of cauline leaves 1-3(6) mm, smooth or scabrous, truncate to acute, ligules of the innovation leaves 0.2-0.5(2.5) mm, scabrous, usually truncate;

innovation blades sometimes distinctly different from the cauline blades, 0.5-2 mm wide, involute, moderately thick, moderately firm, adaxial surfaces usually densely scabrous or hispidulous to softly puberulent, infrequently nearly smooth and glabrous;

cauline blades subequal or the midcauline blades longest or the blades gradually reduced in length distally, 0.5-3 mm wide, flat, folded, or involute, usually thin, usually withering, abaxial surfaces smooth or scabrous, apices narrowly to broadly prow-shaped, flag leaf blades 0.5-5(6) cm.

closed for 1/10 – 1/5 their length, terete, bases of basal sheaths glabrous, distal sheath lengths (0.6)0.88-1.64 times blade lengths;

ligules 0.5-1.5(3) mm, sparsely to densely scabrous, apices truncate to obtuse, ciliolate;

blades 0.8-3 mm wide, mostly flat, thin, soft, appressed or abruptly ascending to spreading, straight or somewhat lax, apices narrowly prow-shaped.

intravaginal or intra- and extravaginal.

all or mostly extravaginal.

2-10(12) cm, usually erect, contracted or loosely contracted, narrowly lanceoloid to ovoid, congested or moderately congested, with 10-100 spikelets and 1-3(5) branches per node;

branches 0.5-4(5) cm, erect or steeply ascending, fairly straight, slender to stout, terete to angled, smooth or scabrous, with 1-15 spikelets.

(1.5)3-15(17) cm, lengths generally 2.5-4 times widths at maturity, usually erect, lax in shade forms, narrowly lanceoloid to ovoid, sparsely to moderately congested;

nodes with 2-5 branches;

branches 0.4-8(9) cm long, 1/4-1/2 the panicle length, ascending to widely spreading, fairly straight, slender to moderately stout, angled, angles moderately to densely scabrous.

(3)4-10 mm, lengths to 3 times widths, broadly lanceolate to narrowly ovate, laterally compressed, not sexually dimorphic;

florets 2-6;

rachilla internodes 0.5-1.2 mm, smooth or scabrous.

3-6 mm, lengths 2-3 times widths, lanceolate to narrowly ovate, laterally compressed, usually not glaucous;

florets (1)2-3(5);

rachilla internodes usually shorter than 1 mm, smooth, muriculate, or scabrous, glabrous, hispidulous, or sparsely to densely puberulent, proximal internodes frequently curved.

lanceolate, distinctly keeled;

lower glumes 3-veined, distinctly shorter than the lowest lemmas;

calluses glabrous or diffusely webbed, hairs less than 1/4 the lemma length;

lemmas (3)4-7 mm, lanceolate to broadly lanceolate, distinctly keeled, membranous to thinly membranous, smooth or sparsely to densely scabrous, glabrous or the keels and/or marginal veins puberulent proximally, lateral veins obscure to prominent, margins glabrous, apices acute;

palea keels scabrous, intercostal regions glabrous;

anthers vestigial (0.1-0.2 mm), aborted late in development, or 2-3.5 mm.

lanceolate to broadly lanceolate, distinctly keeled, keels smooth or sparsely scabrous;

lower glumes 3-veined, long- or abruptly tapered to a slender point, lengths 4.5-6.3 times widths;

calluses usually webbed, infrequently glabrous in depauperate alpine specimens, webs usually scant, less than 1/2(2/3) the lemma length, frequently minute;

lemmas 2.4-4 mm, lanceolate, distinctly keeled, straight or gradually arched, not abruptly inwardly arched at the junction with the scarious apices, keels and marginal veins short-villous, hairs extending 2/3 – 3/4 the keel length, lateral veins usually glabrous, rarely sparsely puberulent, obscure, intercostal regions smooth, sometimes weakly muriculate, glabrous, margins not or slightly inrolled, glabrous, apices acute, usually partially bronze-colored;

palea keels scabrous, intercostal regions glabrous;

anthers (1.1)1.3-2.5 mm.

= 28, 28+11, 56, 56+11, 59, ca. 70.

= 28, 42, 56.