330 POACE^. 



Panicle dense, often lobed or interrupted, 5-10-25 cm. long, rays 

 n-owded and flower-bearing from the base. Spikelets pale green or 

 purple, minutely pubescent, about 1-5 mm. long; empty glumes 

 nearly equal, abruptly-pointed, when spread; floral glume broad, 

 oval, obtuse, minutely 5-tootlied, 5-nerved, awnless, but little over 

 1 mm. long; palea from half the length of its glume to nearly its 

 length. 



Utah, Jones 1014; Oregon, Howell; Mexico (Jalisco), Palmer 

 341, 230. 



Texas to California and Mexico in moist places ; also found in 

 southern Europe and Asia. 



17. A. exarata Trin. Unif. 205 (1824). A. constridus Vasey, 

 in numerous distributions. A. arenaria Scribn., not Gouan. nor 

 Schur. 



Culms erect, 30-60, sometimes 90-120 cm. high, from ^^erennial 

 or annual roots. Sheaths smooth or scabrid, the lower often longer 

 than the internodes; ligule decurrent, 3-5 mm. long; blades usually 

 erect, flat, slightly scabrous or very rough, those of the culm 6-15 

 cm. long, 2-5-8 mm. wide; leaves of sterile shoots shorter. Pan- 

 icle exserted, erect, dense, somewhat lobed, pale green or tinged 

 with purple, varying much in size, 6-20 cm. long, 6-30 mm. broad, 

 often interrupted more or less below; rays in sets of 3-6, numerous, 

 rough, mostly flower-bearing to the base. Spikelets acute, 3.1-3 

 mm. long, empty glumes very nearly equal, though tlie lower 

 usually the longer, scabrous, strongly so on the keel; floral glume 

 awnless, thin to rather firm and brittle, broad, concave, truncate- 

 toothed, grooved on the back, 4-nerved above, 5-nerved below. 

 ].3-1.8 mm. long; palea 0-0.5 mm. long. Stamens 3. 



Wisconsin to Oregon, California, and Arizona. 



'•' It occurs in various forms m all the collections made in tlie 

 State [California], ranging from Sitka to California and eastward 

 to Colorado and Xew Mexico. No other grass found upon the 

 coast presents such a variety of puzzling disguises as this. Speci- 

 mens from wet grounds are 3-4 feet high, while those from dry 

 mountain-sides are only as many inches. The panicle varies from 

 a few inches to 1 foot in length. In mountain forms the leaves are 



