No. 2. 

 HILARIA RIGID A (Thurb.) Scrib. (Pleuraphis riqida. Thurb.) 



Plant perennial, rigid, woody throughout, except the young growth, with 

 hai*d creeping rootstock sending up scaly branches. 



Culms spreading or ascending, branching freely, solid, 1 to 2 feet tall, woolly 

 below. 



Leaves of rootstock appressed. scarious scales; of culm often 2-ranked and 

 rather crowded; sheaths longer than internodes, close, woolly; blades involute, 

 pungent, rigid. 1 to 3 inches long; lignle a dense white, woolly collar. 



Inflorescence a narrow, white or purplish spike. 2 to 3 inches long, formed 

 of obovate clusters of 3 sessile spikelets at each node of the rachis. 



Spikelets; lateral ones in the cluster stauiinate and 2- to 3-flowered, middle one 

 perfect and 1-flowered; empty glumes all about 3 lines long, forming an involucre 

 about the cluster; first glume of staminate spikelet oblong, wider above, oblique, 

 conspicuously ciliate, 5-nerved, 1 or 2 of the nerves on one side extended in short 

 dorsal awns, second glume obovate, 2dobed and ciliate above, 5-to 6-nerved, with 

 1 or 2 dorsal awns; floral glumes oblong or wedge-shaped, nearly equally 2-lobed 

 at apex or merely obtuse, ciliate, 3-nerved, midnerve slightly excurrent. and one 

 lateral nerve rather obscure, 2 to 2^ lines long; palet oblong, truncate, slightly 

 scabrous on the two nerves above, 2 lines long; empty glumes of perfect 

 flower equal, at the back of the cluster, narrow, cuneate, oblique above, 4 to 

 G awned, ciliate, 2 to 3 lines long including awns; floral glume oblong, equally 

 2-lobed, ciliate, 2 to 3 lines long, 3-nerved, lateral nerves equal and slightly excur- 

 rent, midneiwe excurrent in an awn + to 1 line long; palet lance-oblong, obtuse, 

 ciliate or lacerate at apex, 2-nerved, 2 to 3 lines long; stigmas 2, long, plumose. 



Grains; no mature grains found. 



Pla.te II; a to d, parts of staminate flower: a, first empty glume; b. second 

 empty glume; c, floral glume; d, palet; e, perfect flower with its two empty 

 ghimes; /to /t, parts of perfect flower; /'. floral glume; </. palet; h. empty glume. 



New Mexico and Arizona; almost the only grass on the driest desert laud; 

 commonly called Gayetta grass. It is considered a valuable grass. 



