GENUS 34. 



GRASS FAMILY. 



187 



8. Muhlenbergia ambigua Torr. Minnesota Drop- 

 seed. Fig. 446. 



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



Glabrous, culms i tall or lower, erect, branched, smooth. 

 Sheaths shorter than the internodes; ligule about i" long 

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

 panicle i'~3' long, rigid, it:; 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, a.nd 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. 



I'aseya 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"-z" v/ide, erect, flat, rough; 

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

 branches i'-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 c; 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. 

 ii : 48. 1898. 



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



A smooth and glabrous annual. Culms slender, up 

 to l tall, but usually i that height; ligule about i" 

 long, aciue; blades erect, up to 2' long, ' wide, flat, 

 involute; panicle slenc'or, sometimes interrupted be- 

 low, i'-2i' long, the slender branches appressed; 

 spikeleti, exclusive of the short awn when present, 

 a little over i" 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. 



