Flora of North America species comparison

35-80(100) cm, smooth, glabrous throughout;

nodes usually not exposed.

15-65 cm, glabrous, smooth.

closed for less than 1/2 their length, usually glabrous, sometimes pubescent, strongly reined, persistent or slowly shredding into fibers;

collars glabrous;

ligules (0.2)0.3-0.8(1) mm;

blades 0.5-1.3 mm in diameter when conduplicate, to 2.5 mm wide when flat, persistent, abaxial surfaces glabrous and smooth, adaxial surfaces scabrous or pubescent, veins 5-9(12), ribs 5-9, blades of the lower cauline leaves usually reduced to stiff horny points, blades of the upper cauline leaves longer and more flexuous;

abaxial sclerenchyma in strands about as wide as the adjacent veins;

adaxial sclerenchyma developed;

pillars and girders often present.

closed for less than 1/2 their length, lower sheaths glabrous or retrorsely hirsute, persistent, upper sheaths glabrous;

collars glabrous;

ligules (0.2)0.3-0.5(1) mm;

blades all alike, 0.4-0.8 mm in diameter, conduplicate, abaxial surfaces sparsely scabrous, adaxial surfaces scabrous to pubescent, veins 5-7, ribs (1)3-5;

abaxial sclerenchyma in (3)5-7 narrow to broad strands, usually wider than the adjacent veins;

adaxial sclerenchyma absent.

(4)8-15 cm, open or somewhat contracted, with 1-2 branches per node;

branches lax, spreading or loosely erect, lower branches with 2+ spikelets.

5-15 cm, loosely contracted, with 1-2(3) branches per node;

branches erect, lower branches with 2+ spikelets.

9-15 mm, with (2)3-6(7) florets.

(6)7-9(11) mm, with (2)4-6 florets.

exceeded by the upper florets, ovate-lanceolate to lanceolate, glabrous, smooth or scabridulous distally;

lower glumes (2.4)2.8-5 mm, distinctly shorter than the adjacent lemmas;

upper glumes 4.5-7(8.5) mm;

lemmas (4.8)6-8.5 mm, lanceolate to ovate-lanceolate, glabrous, smooth or slightly scabrous, apices acute, unawned or awned, awns 0.2-1.5(2) mm;

paleas about as long as the lemmas, intercostal region scabrous or puberulent distally;

anthers (2)2.5-4(5) mm;

ovary apices densely pubescent.

exceeded by the upper florets, lanceolate, scabrous distally;

lower glumes 2.5-4 mm;

upper glumes (2.8)3-5 mm;

lemmas (3.8)4-6 mm, glabrous, smooth or scabrous distally, awns 1-2.5 mm;

paleas slightly shorter than the lemmas, intercostal region scabrous or puberulent distally;

anthers 2.2-3.5 mm;

ovary apices sparsely pubescent.

= 28.

= 28.