Flora of North America species comparison

30-100 cm, erect;

nodes (2)3-4(5), glabrous or pubescent;

internodes mostly glabrous, puberulent near the nodes.

annual, not woody, not branching above the base;

internodes usually hollow, rarely solid.

glabrous or pilose, midrib of the culm leaves not abruptly narrowed just below the collar;

auricles absent;

ligules to 2.5 mm, glabrous, truncate or obtuse, erose or lacerate;

blades (3)10-25(35) cm long, 2-5(6) mm wide, flat, not glaucous, both surfaces usually glabrous, sometimes the adaxial surface pilose.

closed, margins united for most of their length;

collars without tufts of hair on the sides;

auricles sometimes present;

ligules membranous, sometimes shortly ciliate, those of the upper and lower cauline leaves usually similar;

pseudopetioles absent;

blades linear to narrowly lanceolate, venation parallel, cross venation not evident, without arm or fusoid cells, cross sections non-Kranz, epidermes without microhairs, not papillate.

7-20 cm, open, nodding, often 1-sided;

branches slender, ascending to spreading, often recurved and flexuous.

usually terminal panicles, sometimes reduced to racemes in depauperate plants;

disarticulation above the glumes and beneath each floret.

12-38 mm, elliptic to lanceolate, terete to moderately laterally compressed, with (3)5-11(13) florets.

5-80 mm, not viviparous, terete to laterally compressed, with 3-30 bisexual florets, distal florets sometimes reduced;

rachillas prolonged beyond the bases of the distal florets.

usually pubescent, rarely glabrous;

lower glumes 5-7(9) mm, usually 3-veined, sometimes 1-veined;

upper glumes 6-10 mm, 3-veined, not mucronate;

lemmas 8-14 mm, elliptic, rounded over the midvein, usually pubescent or pilose, margins often with longer hairs, backs and margins rarely glabrous, apices acute or obtuse to truncate, entire;

awns (1)2-3(3.5) mm, straight, arising less than 1.5 mm below the lemma apices;

anthers (1)2-3 mm.

usually unequal, rarely more or less equal, exceeded by the distal florets, usually longer than 1/4 the length of the adjacent florets, lanceolate, 1-9(11)-veined;

florets terete to laterally compressed;

calluses glabrous, not well developed;

lemmas lanceolate to ovate, rounded or keeled over the midvein, herbaceous to coriaceous, 5-13-veined, veins converging somewhat distally, apices usually minutely bilobed to bifid, rarely entire, usually awned, sometimes unawned, awns unbranched, terminal or subterminal, usually straight, sometimes geniculate;

paleas usually shorter than the lemmas;

lodicules 2, glabrous, not veined;

anthers 3;

ovaries with hairy apices;

styles 2, bases free.

narrowly ellipsoid to linear, longitudinally grooved;

hila linear;

embryos about 1/6 the length of the caryopses.

= 7.

= 14.