MANUAL OF THE GRASSES OF THE UNITED STATES 



497 



forming a short callus below the 

 floret; glumes about equal, 1-nerved, 

 long-acuminate, mostly as long as the 

 spikelet or longer; lemmas bidentate, 

 3-nerved, the lateral nerves near the 

 margin, the midnerve usually excur- 

 rent as a short awn, the margins long- 

 ciliate; palea broad, the nerves near 

 the margin. Annuals or perennials 

 with simple panicles, the spikelets 

 short-pediceled along one side of the 

 main branches. Type species, Tricho- 

 neura hookeri Anderss. Name from 

 Greek thrix, hair, and neuron, nerve, 

 alluding to the ciliate nerves of the 

 lemma. 



Figure 729. — Leptochloa nealleyi. Panicle, X 1; two 

 views of floret, X 10. (Fisher 25, Tex.) 



1. Trichoneura elegans Swallen. 

 (Fig. 732.) Annual, branching at base; 

 culms erect, rather robust, or ascend- 

 ing, 40 to 110 cm. tall, several-noded ; 

 sheaths scaberulous; blades flat, or 

 subinvolute toward the tip, scabrous, 

 elongate, 3 to 7 mm. wide; panicle 

 erect, 10 to 18 cm. long, the axis 

 angled, scabrous ; branches numerous, 

 stiffly ascending, the lower 5 to 8 cm. 

 long, rather densely flowered; spike- 

 lets mostly 5- to 8-flowered, 9 to 10 

 mm. long; glumes about equaling the 

 spikelet, the setaceous tips slightly 



Figure 730. — Leptochloa scabra. Panicle, X 1; two 

 views of floret, X 10. (Tracy 8388, La.) 



spreading ; lemmas scaberulous 

 toward the obtuse minutely lobed 

 summit, the awn minute, the mar- 

 gins conspicuously ciliate on the 

 lower half to two-thirds, the hairs as 

 much as 1 mm. long. O — Sandy 

 soil, southern Texas. 



99. TRIP0GON Roth 



Spikelets several-flowered, subses- 

 sile, appressed in 2 rows along one 



Figure 731. — Leptochloa panicoides. Panicle, X 1; 

 two views of floret, X 10. (Tracy 7451, Miss.) 



