212 MISC. PUBLICATION 200, TJ. S. DEPT. OF AGRICULTUEE 



4 to 5 mm long, pubescent on the callus and on the lower two-thirds 

 of the midnerve and margin, the apex obtuse, entire, the midnerve not 



or scarcely excurrent; palea a little shorter than 

 the lemma, pubescent along the margins; grain 

 elliptic, 3 mm long. 91 (Tridens buckleyanus 

 Nash.) — -Rocky wooded slopes, southern Texas. 



6. Triodia drummondii Scribn. and Kearn. 

 (Fig. 410.) Culms slender, erect, 1 to 1.5 m 

 tall, with creeping scaly rhizomes ; sheaths glabrous 

 or the lower pubescent; blades flat, elongate, 2 to 

 7 mm wide; panicle purplish, narrow, rather loose, 

 nodding, 10 to 20 cm long, the branches appressed 

 or narrowly ascending; spikelets short-pediceled, 

 3- to 5-flowered, 7 to 10 mm long; glumes 

 broad, mucronate from a notched apex; lemmas 

 about 5 mm long, pilose on the callus and on the 

 lower half of the midnerve and margins, the sum- 

 mit lobed, the 3 nerves excurrent less than 1 mm; 

 palea glabrous, a little shorter than the lemma, 

 bowed out below. % (Tridens drummondii 

 Nash.) — Sandy woods, Coastal Plain, South 

 Carolina to Florida and Louisiana (fig. 411). 



7. Triodia langloisii (Nash) Bush. (Fig. 412.) 

 Culms slen- 

 der, erect, 60 

 to 100 cm 

 tall; blades 

 flat or loose- 

 ly involute, 

 1 to 5 mm 

 wide ; panicle 

 or purplish, 



the branches 



Figure 408.— Triodia con' 

 gent a. Panicle, X 1; 

 floret, X 5. (Tracy 8879, 

 Tex.) 



open, ovoid, pale 

 8 to 20 cm long, 

 ascending, 3 to 8 cm long ; spike- 

 lets short-pediceled (pedicels 

 less than 1 mm) along' the sim- 

 ple branches, 4- to 7-flowered, 

 4 to 6 mm long, nearly as broad, 

 the florets crowded; glumes 

 broad, subacute; lemmas 3 to 

 4 mm long, mucronate from a 

 minutely lobed apex, the lateral 

 nerves scarcely or barely ex- 

 serted, pilose on the midnerve 

 and margins on the lower half; 

 palea nearly as long as the lem- 

 ma, the keels bowed out below. 

 91 (T. ambigua Benth., not R. Br.; Tridens ambiguus Schult.) — 

 Wet pine barrens, on the coast, South Carolina to Florida and Texas 

 (fig. 413). Plants of the Atlantic Coast (Triodia elliottii Bush) 

 mostly have smaller spikelets with shorter lemmas than those of the 

 Gulf region ( T. langloisii), but there are numerous intergrades through- 

 out the range. 



Figure 409.— Triodia bucklcyana. Panicle, X 1; 

 floret, X 5. (Tharp 2996, Tex.) 



