402 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



FIGURE 831. Distribution of 

 Sporobolus heterotepis. 



about 3 mm long; first glume about half as long, the second glume as 



long as the acute lemma or a little longer. 91 (S. junceus Kunth.) 



Pine barrens of the Coastal Plain, southeastern Virginia to Florida 



and Texas (fig. 836). Common in the high pineland of Florida. 

 17. Sporobolus purpurascens (Swartz) Hamilt. (Fig. 837.) 



Resembling S. gracilis; blades flat or folded, 1 to 3 mm wide; panicle 

 10 to 15 cm long, more contracted than in S. 

 gracilis, the shorter branches numerous in the 

 whorls, ascending or appressed, florif erous nearly 

 to the base; spikelets about as in S. gracilis, 

 greenish-purple. 91 Sandy prairies, south- 

 ern Texas and eastern Mexico; West Indies 

 to Brazil. 



18. Sporobolus argutus (Nees) Kunth. (Fig. 

 838.) Perennial, in spreading or prostrate tufts ; 



culms 10 to 40 cm tall; leaves crowded at the base, the sheaths pilose 



at the throat; blades flat, mostly less than 10 cm long, 2 to 4 mm 



wide, sparsely long-ciliate toward 



the base ; panicle pale, pyramidal, 



3 to 7 cm long, rarely longer, 



the branches spreading, somewhat 



viscid, 1 to 3 cm long, naked 



below, closely flowered above, 



the lowermost in a distinct whorl ; 



spikelets a little more than 1 mm 



long; first glume minute, the sec- 

 ond as long as the lemma and 



palea. 91 Sandy or gravelly 



soil, especially along streets and 



along the seashore and in the 



interior in alkaline soil, Kansas 



and Colorado to Louisiana and 



Texas ; Arizona ; southern Florida ; 



tropical America (fig. 839). 



19. Sporobolus domingensis 

 (Trin.) Kunth. (Fig. 840.) Dif- 

 fering from S. argutus in the 

 usually larger size (culms some- 

 times as much as 1 m tall), broader 

 blades, 3 to 6 mm wide, and stiffer 

 longer panicles, the branches as- 

 cending or appressed, overlapping, 

 less regularly in whorls ; spikelets 



oK^T*- o 1^. fV.rt -fi-r.o-<- ^In^ FIGURE 832. Sporobolus curtissii. Panicle, X 1; 



about 2 mm long, the first glume glumes and fl ret) x 10. (Bitting 1050, Fia.) 

 half as long. 91 Coral sand 



and rocks along the coast of southern Florida, mostly on the Keys, 

 north to Sanibel Island; West Indies. 



20. Sporobolus cryptandrus (Torr.) A. Gray. SAND DROPSEED. 

 (Fig. 841, A.) Perennial, usually in rather small tufts; culms erect 

 or spreading, sometimes prostrate, 30 to 100 cm tall; sheaths with a 

 conspicuous tuft of long white hairs at summit; blades flat, 2 to 5 mm 

 wide, more or less involute in drying, tapering to a fine point ; panicles 



