8. Muhlenbergia Ambigua Torr. Minnesota Drop-Seed

Fig. 446

Muhlenbergia ambigua Torr. Nicollet's Rep. 164. 1843.

Glabrous, culms 1° tall or lower, erect, branched, smooth. Sheaths shorter than the internodes; ligule about 1/2" long erose-truncate; blades 1-3' long, \"-2" wide, scabrous; panicle 1-3' long, rigid, its branches 1/2'-1' long, dense, ap-pressed; outer scales of the spikelet awn-pointed, unequal, the longer about 2" in length and exceeding the body of the third scale which is scabrous, villous, and attenuate into an awn 2-3 times its length; a fourth narrow awned scale is nearly always present.

Along a lake shore in Minnesota.

8 Muhlenbergia Ambigua Torr Minnesota Drop Seed 4468 Muhlenbergia Ambigua Torr Minnesota Drop Seed 447

9. Muhlenbergia Comata (Thurb.) Benth. Hairy Dropseed

Fig. 447

Vaseya comata Thurb. Proc. Phila. Acad. 1863: 79. 1863. M. comata Benth.; Vasey, Cat. Grasses U. S. 39. 1885.

Culms 1°-2 1/2° tall, erect, slender, smooth and glabrous-Sheaths shorter than the internodes, smooth or slightly scabrous; ligule about 1/2" long, truncate, naked or minutely ciliate; blade:; 2 1/2-5' long, l"-2" wide, erect, flat, rough; panicle often tinged with purple, 2-4' in length, dense, branches 1/2'-1 1/2' long, erect; outer scales of the spikelet equal, or the second a little the longer, smooth, scabrous on the keel; third scale shorter, smooth and glabrous, bearing an awn 2-3 times its length, the basal hairs silky, erect, fully as; long as the scale.

On prairies, Montana to Washington, south to Kansas (?) and Colorado. Aug.-Sept.

10. Muhlenbergia Simplex (Scribn.) Rydb. Slender Dropseed

Fig. 448

Sporobolus simplex Scribn. Bull. U. S. Dep. Agr. Agrost. 11: 48. 1898.

M. simplex Rydb. Bull. Torr. Club, 32: 600. 1905.

A smooth and glabrous annual. Culms slender, up to 1° tall, but usually 1/2 that height; ligule about 1" long, acute; blades, erect, up to 2' long, i" wide, flat, involute; panicle slender, sometimes interrupted below, 1'-2 1/2' long, the slender branches appressed; spikelets, exclusive of the short awn when present, a little over 1" long, the outer scales less than i as long as the spikelet, rounded or truncate at the erose apex, the flowering scale very acute and often with a short point or awn.

In meadows and along brooks, Montana to Nebraska and Colorado. Aug. and Sept.

10 Muhlenbergia Simplex Scribn Rydb Slender Dropse 448

11. Muhlenbergiabrevifdlia (Nutt.) Nash. Short-Leaved Rush-Grass

Fig. 449

Agrostis brevifolia Nutt. Gen. 1: 44. 1818.

Sporobolus Richardsonis Merrill, Rhodora, 4: 46. 1902.

Sporobolus brevifolius Scribn. Mem. Torr. Club, 5: 39. 1895.

Smooth and glabrous, culms 6'-18' tall, arising from a horizontal rootstock, erect, slender, decumbent and branching above. Sheaths much shorter than the internodes; ligule 3/4"-1" long, acutish; blades 1/2'-2' long, involute-setaceous; panicle 1/2-3' in length, usually about 1 1/2', linear, its branches 1/4'-1/2' long, erect orappressed; spikelets 1 1/4"-1 1/2" long, the outer scales unequal, about one-half as long as the third, scabrous on the* keel and at the apex; third scale long-acuminate, sometimes cuspidate, scabrous toward the apex.

In meadows and along rivers, Anticosti Island and Maine to British Columbia, south in the mountains to New Mexico and California. Summer.

11 Muhlenbergiabrevifdlia Nutt Nash Short Leaved R 449