MANUAL OF THE GRASSES OF THE UNITED STATES 491 



spikelet narrower, with one long and mentary (var. abortivus (Fourn.) 



2 short awns. O — Open ground, Beetle), but such spikelets and also 



mountains of southern Arizona, south central spikelets with reduced awns 



to northern South America. Lateral are found in plants with normal 



spikelets sometimes reduced or rudi- spikelets. 



TRIBE 7. CHLORIDEAE 

 97. LEPTOCHLOA Beauv. Sprangletop 



Spikelets 2- to several-flowered, sessile or short-pediceled, approximate or 

 somewhat distant along one side of a slender rachis, the rachilla disarticulating 

 above the glumes and between the florets; glumes unequal or nearly equal, 

 awnless or mucronate, 1-nerved, usually shorter than the first lemma; lemmas 

 obtuse or acute, sometimes 2-toothed and mucronate or short-awned from 

 between the teeth, 3-nerved, the nerves sometimes pubescent. Annuals or 

 perennials, with flat blades and numerous usually slender spikes or racemes 

 borne on a common axis forming a long or sometimes short panicle. Type 

 species, Leptochloa virgata. Name from Greek leptos, slender, and chloa, grass, 

 alluding to the slender spikes. 



The only species of Leptochloa important as a forage grass is L. dubia, or 

 sprangletop, of the Southwest, useful for grazing and for hay. 



Plants perennial. 



Lemmas broad, notched at apex, the lateral nerves glabrous 1. L. dubia. 



Lemmas acute or awned, the lateral nerves pubescent. 



Lemmas about 3 mm. long; panicle flabellate, the axis short...- 2. L. chloridiformis. 

 Lemmas about 1.5 mm. long; panicle oblong, the axis relatively long. 



Sheaths and blades glabrous; lemmas awnless or nearly so 3. L. virgata. 



Sheaths and blades sparsely pilose; lemmas awned 4. L. domingensis. 



Plants annual. 



Sheaths papillose-pilose; first floret not longer than the second glume; spikelets mostly 



1 to 2 mm. long 5. L. filiformis. 



Sheaths smooth or scabrous, not pilose; spikelets more than 2 mm. long. 

 Lemmas awned, awns sometimes minute. Culms freely branching. 



Lemmas viscid on the back; panicle oval, usually less than 10 cm. long, the longer 

 branches usually less than 5 cm. long; second glume 1.5 mm. long. 



6. L. VISCIDA. 

 Lemmas not viscid; panicle more than 10 cm. long, the longer branches usually as 



much as 10 cm. long; second glume 3 mm. long 7. L. fascicularis. 



Lemmas awnless or mucronate only. 

 Lemmas obtuse, sometimes mucronate. 



Spikelets 5 to 7 mm. long, 6- to 9-flowered, lead color 8. L. uninervia. 



Spikelets 2 to 3 mm. long, 3- to 4-flowered, pale 9. L. nealleyi. 



Lemmas acuminate. 



Sheaths scabrous, keeled and compressed 10. L. scabra. 



Sheaths smooth or slightly scabrous near apex, scarcely keeled or compressed. 



11. L. PANICOIDES. 



1. Leptochloa dubia (H. B. K.) 



Nees. Green sprangletop. (Fig. duced specimens only 2-flowered), 5 



721.) Perennial; culms wiry, erect, to 10 mm. long; lemmas broad, gla- 



50 to 100 cm. tall; sheaths glabrous; brous on the internerves, obtuse or 



blades flat or sometimes folded or emarginate, the midnerve sometimes 



loosely involute, scabrous, as much extending into a short point, the 



as 1 cm. wide, usually narrower; florets at maturity widely spreading, 



panicle of few to many spreading or very different in appearance from 



ascending racemes 3 to 12 cm. long, their early phase. 91 — Rocky hills 



approximate or somewhat distant on and canyons and sandy soil, southern 



an axis as much as 15 cm. long; Florida; Oklahoma and Texas to 



spikelets 5- to 8-flowered (or in re- Arizona, south through Mexico; Ar- 



