Flora of North America species comparison

20-80 (100) cm tall, (1.5)2-3.5 mm thick, not or only slightly spongy, sometimes rooting at the lower nodes.

60-100 cm tall, 1.5-5 mm thick, often decumbent and rooting at the lower nodes.

smooth to scabridulous, keeled, sometimes weakly so;

ligules 1-4 mm, usually rounded, sometimes acute to mucronate, erose-lacerate;

blades 12-30 cm long, 2-6 mm wide, abaxial surfaces smooth or scabridulous, adaxial surfaces scabridulous to scabrous.

glabrous, keeled;

ligules 4-12 mm;

blades 9-25 cm long, 2-7 mm wide, often floating, abaxial surfaces smooth, adaxial surfaces of the midcauline leaves densely papillose, glabrous.

6-25 cm long, 2.5-21 cm wide, pyramidal, open, nodding;

branches 5-13 cm, straight to lax, lower branches usually strongly divergent to drooping at maturity, sometimes ascending, with 15-50 spikelets, these often confined to the distal 2/3;

pedicels 0.5-7 mm.

18-40(50) cm long, 0.5-2(5) cm wide, arching, usually narrow, open at anthesis, bases often enclosed in the upper leaf sheath at maturity;

branches 5-10(15) cm, usually 1-3(5) per node, usually appressed to strongly ascending, occasionally spreading, longer branches with 3-6 spikelets;

pedicels 1.2-5 mm.

1.8-4 mm long, 1.2-2.9 mm wide, laterally compressed, oval in side view, with 3-7 florets.

9-22 mm long, 0.8-2.5 mm wide, cylindrical and terete, except at anthesis when slightly laterally compressed, rectangular in side view, with 8-12 florets.

ovate, 1-1.5 times longer than wide, narrowing from midlength or above, veins terminating below the apical margins, apices often splitting with age;

lower glumes 0.5-1.2 mm, rounded to obtuse;

upper glumes 0.6-1.2 mm, acute or rounded;

rachilla internodes 0.1-0.6 mm;

lemmas 1.2-2 mm, ovate in dorsal view, veins raised, scabridulous over and between the veins, apices acute, prow-shaped;

paleas slightly shorter than to equaling the lemmas, lengths 1.5-3 times widths, keeled, keels not winged, tips pointing towards each other, apices narrowly notched between the keels;

anthers 2, (0.2)0.4-0.6 mm, purple or yellow.

elliptic, apices rounded to obtuse, sometimes erose;

lower glumes 1.2-2.2 mm;

upper glumes 2-3.8 mm, rounded;

rachilla internodes 0.6-3.5 mm;

lemmas 2.7-5.4 mm, veins raised, scabridulous or smooth, intercostal regions usually smooth, sometimes scabridulous, midvein terminating about (0.1)0.2 mm short of the apical margin, apices usually acute, sometimes obtuse, entire or almost so;

paleas usually shorter than to equaling the lemmas, sometimes exceeding them by up to 0.5 mm, keels narrowly winged, apices bifid, teeth to 0.2 mm, parallel to weakly incurved;

anthers 3, 0.4-1.5 mm.

0.5-2 mm.

1.2-2 mm.

= 20 [reports of 28 are questionable].

= 20.