MANUAL OF THE GRASSES OF THE UNITED STATES 



173 



\p 



F 



16. DISSANTHELIUM Trin. 



Spikelets mostly 2-flowered, the rachilla 

 slender, disarticulating above the glumes 

 and between the florets; glumes firm, near- 

 ly equal, acuminate, much longer than the 

 lower floret, mostly exceeding all the florets, 

 the first 1-nerved, the second 3-nerved; lem- 

 mas strongly compressed, oval or elliptic, 

 acute, 3-nerved, the lateral nerves near the 

 margin; palea somewhat shorter than the 

 lemma. Annuals or perennials with narrow ^ 

 panicles. Type species, Dissanthelium supin- 

 um Trin. Name from Greek, dissos, double, 

 and anthelion, a small flower, alluding to 

 the two small florets. 



1. Dissanthelium californicum (Nutt.) 

 Benth. (Fig. 345.) Annual, lax; culms 

 more or less decumbent or spreading, about 

 30 cm tall; blades flat, 10 to 15 cm long, 2 to 

 4 mm wide ; panicle 10 to 15 cm long, narrow 

 but rather loose, the branches in fascicles, 

 ascending, slender, flexuous, some of them 

 floriferous to base; glumes narrow, acute, 

 nearly equal, about 3 mm long; lemmas 

 pubescent, nearly 2 mm long. © — Open 

 ground, islands off the southern coast of 

 California and of Baja California. 



17. REDFIELDIA Vasey 



Spikelets compressed, mostly 3- or 4- 

 flowered, the rachilla disarticulating above 

 the glumes and between the florets; glumes 

 somewhat unequal, 1-nerved, acuminate; 

 lemmas chartaceous, 3-nerved, the nerves 

 parallel, densely villous at base; palea as 

 long as the lemma; grain free. A rather tall 

 perennial, with extensive rhizomes, and a 

 large panicle with diffuse capillary branches. 

 Type species, Redfieldiaflexuosa. Named for 

 J. H. Redfield. 



1. Redfieldia flexuosa (Thurb.) Vasey. 

 Blowout grass. (Fig. 346.) Culms tough, 

 60 to 100 cm tall, the rhizomes long, slender; 

 blades glabrous, involute, elongate, flexu- 

 ous, tapering to a fine point ; panicle oblong, 

 one-third to half the entire length of the 

 culm; spikelets 5 to 7 mm long, broadly V- 

 shaped, the glumes acuminate, about half 

 as long as the spikelet; lemmas acute, 

 sometimes mucronate, 4 to 5 mm long. ^^iS^^^i 

 % —Sand hills, South Dakota to Okla- *?*.*<> ret > x 10 - < Trask 324 > 

 homa, west to Colorado (Fort Garland) 

 and Arizona (Moki Reservation) (fig. 347). A sand-binding grass. 



