[++] Glumes equal or the middle one longer.
5. A. strícta, Michx. Culms (2–3° high) densely tufted from a perennial root, bearing a (1°) long spiked panicle; leaves involute-thread-form, long, rigid, sometimes downy; awns about the length of the glumes (6´´) or the lateral one third shorter.—Va. and southward.
6. A. oligántha, Michx. Culms (6–20´ high) tufted from an annual root, bearing a loosely few-flowered raceme; leaves short, somewhat involute when dry; lower glume 3–5-nerved (nearly 1´ long); awns capillary, 1½–3´ long, much exceeding the slender spikelet.—Va. to Ill., and common southwestward.
7. A. purpùrea, Nutt. Perennial; culms (1° high or less) densely tufted, spreading; leaves revolute and filiform, short; panicle loose, of rather few slender-pedicellate spikelets; lower glumes thin, 1-nerved, loose, the outer about half the length of the inner, which is 8–10´´ long; awns 2–4´´ long.—Minn. and Dak. to Tex.—Very variable.
[++][++] Middle glume shorter than the lower; perennials, simple-stemmed, 2–4° high.
8. A. purpuráscens, Poir. ([Pl. 8.]) Glabrous; leaves long, rather involute; spikelets in a (10–18´) long spiked panicle; lower glumes 1-nerved; awns much longer than the spikelet, the middle one about 1´ long.—Mass. to Mich., Minn., and southward; common.
9. A. lanàta, Poir. Tall and stout; leaves tardily involute, rough above, rigid; sheaths woolly; panicle (1–2° long) spike-like or more compound and open; glumes 1-nerved, 6–8´´ long; middle awn 1´ long.—Del. to Fla.
[*][*] Awns united below into one, jointed with the apex of the glume; root annual.
10. A. tuberculòsa, Nutt. Culm branched below (6–18´ high), tumid at the joints; panicles rigid, loose, the branches in pairs, one of them short and about 2-flowered, the other elongated and several-flowered; lower glumes (1´ long, including their slender-awned tips) longer than the upper, which is tipped with the common stalk (about its own length) of the 3 equal divergently-bent awns (1½–2´ long) twisting together at the base.—Sandy soil, E. Mass. to N. J.; also Wisc., Minn., and southward.
20. STÌPA, L. Feather-Grass. ([Pl. 8.])