Genus 34. 



GRASS FAMILY. 



187 



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 i" long 

 erose-truncate ; blades 1-3' long, i"-2" wide, scabrous; 

 panicle I'-g' long, rigid, its branches i'-i' 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. 



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 i°-2i° tall, erect, slender, smooth and glabrous. 

 Sheaths shorter than the internodes, smooth or slightly 

 scabrous; ligule about ¥' long, truncate, naked or minutely 

 ciliate; blades 2i'-5' long, i"-a" wide, erect, flat, rough; 

 panicle often tinged with purple, 2'-4* in length, dense, 

 branches J'-iJ' 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, bear- 

 ing an awn .2-3 times its length, the basal hairs silky, erect, 

 fully a; 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 i that height; ligule about 1" 

 long, acute; blades erect, up to 2' long, i" wide, flat, ■ 

 involute; panicle slender, sometimes interrupted be- 

 low, i'-2i' 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. 



