[*] Flowering glume barely mucronate or sharp-pointed.
1. M. sobolífera, Trin. Culms ascending (1–2° high), rarely branching; the simple contracted panicle very slender or filiform; lower glumes barely pointed, almost equal, one third shorter than the flower; flowering glume abruptly short-mucronate, equalling the palet.—Open rocky woods, Mass. to Mich., Minn., and southward. Aug.—Spikelets less than 1´´ long.
2. M. glomeràta, Trin. Culms upright (1–3° high), sparingly branched or simple; panicle (2–3´ long) oblong-linear, contracted into an interrupted glomerate spike, long-peduncled, the branches sessile; glumes awned, nearly equal, and (with the bristle-like awn) about twice the length of the unequal very acute flowering glume and palet.—Bogs and wet rocks, common, especially northward. Aug.—Var. ramòsa, Vasey. A stout strict much-branched leafy form, the lower glumes but little longer than the flower. Ill. to Dak.
3. M. Mexicàna, Trin. Culms ascending, much branched (2–3° high); panicles lateral and terminal, often included at the base, contracted, the branches densely spiked-clustered, linear (green and purplish); lower glumes awnless, sharp-pointed, unequal, the upper about the length of the very acute flowering one.—Low grounds; common. Aug. Varies with more slender panicles.
[*][*] Flowering glume bristle-awned from the tip; flowers short-pedicelled.
[+] Lower glumes long and bristle-pointed.
4. M. sylvática, Torr. & Gray. (Pl. 8, fig. 1, 2.) Culms ascending, much branched and diffusely spreading (2–4° long); contracted panicles densely many-flowered; lower glumes almost equal, bristle-pointed, nearly as long as the flowering one, which bears an awn twice or thrice the length of the spikelet.—Low or rocky woods; common. Aug., Sept.
5. M. ambígua, Torr. Culms ascending, clustered and branching, 1° high; panicles contracted, densely many-flowered; spikelet 2-flowered, the upper flower like the lower and perfect, or more frequently reduced to a mere awn at the base of the lower flower; lower glumes nearly equal, long-pointed; flowering glume villous, as long as the lower and equalling the palet, its awn nearly twice longer.—Minn. (shore of Elysian Lake, Waseca Co., Geyer).—A remarkable species, approaching Brachyelytrum in the structure of the spikelet, but with wholly the habit of Muhlenbergia.
[+][+] Lower glumes short or minute, not or scarcely pointed.
6. M. Willdenòvii, Trin. Culms upright (3° high), slender, simple or sparingly branched; contracted panicle slender, loosely flowered; lower glumes slightly unequal, short-pointed, half the length of the flowering one, which bears an awn 3–4 times the length of the spikelet.—Rocky woods; rather common. Aug.