No. 17. 



ORYZOPSIS EXIGUA Thurb. Bot. Wilkes Exp. 481. 



Plant perennial, tufted, with numerous sterile snoots. 



Culms erect, slender, terete, hispid, G to 15 inches high; nodes black, scarcely con- 

 stricted. 



Leaves of sterile shoots numerous, with close striate, hispid sheaths, and narrow 

 involute, wiry, scabrous blades 4 to 7 inches long. Leaves of culm usually 4; lower two 

 with short, overlapping sheaths and blades like the radical leaves, next sheaths above 

 much shorter than tbe internode, upper sheath usually vaginate and longer, upper 

 blades erect, 2 to 4 inches long; ligule membranaceous, acute, 1 to 2 lines long. 



Inflorescence a narrrow secund panicle included at first, 1J to 3 inches long; 

 rachis fiexuous, branches usually in pairs, erect, unequal, the longer bearing usually 2 

 spikelets and the shorter one. 



Spikelets lanceolate, turgid, 1-flowered, 2 J lines long; empty glumes oblong-ovate, 

 barely acute or abruptly acuminate, membranaceous, minutely scabious, equal, 2 to2£ 

 lines long, 3-nerved or 5-nerved at the base, the nerves anastomosing; stipe short, 

 blunt; floret spindle-shaped, 2 to 2h lines long, ^ as thick; floral glume herbaceous, 

 becoming chartaceous, obtuse or with purple teeth at the apex, clothed throughout 

 with short pubescence, 5-nerved, the nerves uuiting above ; awn persistent, minutely 

 hispid, brown, 2 to 3 lines long; palet equaling the glume and like it in texture and 

 pubescence, obtuse or bidentate at the apex; lodicules 2, \ line long; anthers exserted; 

 grain oblong, flattened, oblique at the obtuse apex, yellow, minutely wrinkled, \\ lines 

 long, \ as wide. 



Plate XVII ; a, spikelet partly dissected, enlarged 5 times. 



Oregon and Washington, in the mountains. The persistent awn and elongated 

 floret of this species place it close to Stipa, and indicate that it is difficult to make 

 even an artificial distinction between the two genera. 



