428 



W 



m 



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



25. Sporobolus giganteus Nash. 

 Giant dropseed. (Fig. 614.) Resem- 

 bling S. cryptandrus and >S. contractus; 

 culms 1 to 2 m. tall, erect, robust; 

 blades as much as 1 cm. wide; panicle 

 usually thicker than in S. contractus, 

 less spikelike; spikelets 2.5 to 3 mm. 

 long. % — Mesas and sandhills, 

 Oklahoma and western Texas to Colo- 

 rado and Arizona. 



26. Sporobolus buckleyi Vasey. 

 (Fig. 615.) Perennial, the base 

 strongly compressed; culms erect, 

 slender, 40 to 80 cm. tall; sheaths 

 keeled, pubescent on the margin and 

 collar; blades flat, 4 to 7 mm. wide; 

 panicle open, 10 to 30 cm. long, the 

 slender branches widely spreading, as 

 much as 10 cm. long, solitary, rather 

 distant, naked below, with closely 

 flowered short-appressed branchlets 

 above; spikelets about 1.5 mm. long; 

 glumes narrow, the first a little 

 shorter, the second a little longer than 

 the acute lemma; palea about as long- 

 as the lemma, splitting as the grain 

 (1 mm. long) ripens. 01 — Texas 

 and eastern Mexico. 



27. Sporobolus airoides (Torr.) 

 Torr. Alkali sacaton. (Fig. 616.) 

 Perennial, in large tough bunches; 

 culms erect to spreading, 50 to 100 

 cm. tall; sheaths pilose at the throat; 

 ligule pilose; blades elongate, flat, 

 soon becoming involute, usually less 

 than 4 mm. wide, often flexuous; pan- 

 icle nearly half the entire height of 

 the plant, at maturity half to two- 

 thirds as wide as long, the stiff slen- 

 der branches and branchlets finally 

 widely spreading, naked at base, the 

 spikelets aggregate along the upper 

 half to two-thirds; spikelets 2 to 2.5 

 mm. long, the first glume about half 

 as long, commonly falling toward 



Figuhe 614. — Sporobolus giganteus. Panicle, X 

 glumes and floret, X 10. (Nealley, Tex.) 



included at the base, rarely entirely in- 

 cluded in the sheath. % (S. strictus 

 Merr.) — Mesas, dry bluffs, and sandy 

 fields, Arkansas, Colorado to Nevada, 

 south to western Texas, southeastern 

 California, and Sonora; adventive in 

 Maine. 



Figure 615. — Sporobolus buckleyi. Panicle, X Vi\ glumes and floret, X 10. (Nealley, Tex.) 



