260 MISC. PUBLICATION 200, U. S. DEFT. OF AGRICULTURE 



The species are widespread in the Western States but do not form 

 complete stands. They have forage value when young but at ma- 

 turity the disarticulating joints of the spike, with their pointed 

 rachis joints and long-awned spikelets, are blown about by the wind 

 and often cause injury to stock, penetrating the mouth, nose, and 

 ears, working in by means of the forwardly roughened awns, and 

 causing inflammation. Grazed also after the heads are blown off. 

 The commonest species is S. hystrix. 



Spike much longer than broad; glumes narrowly lanceolate, 2- to 4-nerved. 



1. S. HANSENI. 

 Spike as broad as long or broader; glumes bristle-like, 1- or obscurely 2-nerved. 



Glumes cleft into at least 3 fine divisions 2. S. JUBATUM. 



Glumes entire or 2-cleft 3. S. HYSTRIX 



1. Sitanion hanseni (Scribn.) J. G. Smith. HANSEN SQUIRRELTAIL. 

 (Fig. 511.) Culms 60 to 100 cm tall; sheaths and blades glabrous or 

 scabrous to softly pubescent, the blades flat to 

 subin volute^, 2 to 8 mm wide; spike somewhat 

 nodding or flexuous, 8 to 20 cm long; glumes 

 narrowly lanceolate, sometimes bifid, 2- to 3- 

 nerved, long-awned, lower lemmas about 8 mm 

 long, the awn 4 to 5 cm long, divergent when 

 dry and mature. 01 Open woods and rocky 

 slopes, Idaho to eastern Washington, Utah, and 

 California (fig. 512). Pubescent plants have been 

 differentiated as S. anomalum J. G.[Smith. 



2. Sitanion jubatum J. G. Smith. BIG SQUIR- 

 RELTAIL. (Fig. 513.) Culms erect to ascending, 

 20 to 60 cm tall, rarely taller; foliage glabrous 

 ' (Suksdorf or scabrous to white-villous, the blades flat, often 

 becoming involute, mostly not more than 4 mm 

 wide; spike erect, dense, 3 to 10 cm long, thick and bushy from the 

 numerous long slender spreading awns; glumes split into 3 or more 

 long awns; lemmas mostly 8 to 10 mm long, smooth, or scabrous 

 toward apex, the awns and those of the glumes 

 spreading, 3 to 10 cm long, rarely shorter. 01 

 Rocky or brushy hillsides and open dry 

 woods and plains, Idaho to eastern Washington, 

 south to Utah, Nevada, and Baja California 

 (fig. 514). Occasionally a few of the glumes 

 in a spike are divided into only 2 awns. Short- 

 awned plants have been differentiated as S. 

 breviaristatum J. G. Smith and the more densely pubescent plants as 

 $. villosum J. G. Smith. 



3. Sitanion hystrix (Nutt.) J. G. Smith. SQUIRRELTAIL. (Fig. 

 515.) Culms erect to spreading, rather stiff, 10 to 50 cm tall; foliage 

 from glabrous or jmberulent to softly and densely white-pubescent, 

 the blades flat to involute, rather stiffly ascending to spreading, 5 to 20 

 cm long, 1 to 3 mm wide, rarely as much as 5 mm wide ; spike mostly 

 short-exserted or partly included, erect, 2 to 7 cm, rarely 10 cm long 

 or longer, the glumes very narrow, 1- to 2-nerved, the nerves extend- 

 ing into scabrous awns, sometimes bifid to the middle, or bearing a 

 bristle or awn along one margin; lemmas convex, smooth or scabrous 

 to appressed pubescent, sometimes glaucous, the awns of glumes and 

 lemmas widely spreading, 2 to 10 cm long. 01 Dry lulls, plains, 



FIGURE 511. Sitanion 



FIGURE 512. Distribution of 

 Sitanion hanseni. 



