25 



upper ones short and few (three* to six) flowered, sessile, one-half inch 

 long-, the lower longer, sometimes subdivided, and with long, sheathed 

 peduncles; rhachis liexuous, bristle like at the apex, spikelets about 

 one line long 1 , ovate, lower glume one half as long as the spikelet, ob- 

 tuse, upper glume nine nerved. 



Florida (Chapman, Curtiss, Garber). 



13. P. Eeverchoni, Vasey. (distributed by Keverchon as Setaria uni- 

 seta). — Culms filiform from a thick, strong rootstock, erect, 10 to 18 

 inches high, simple ; leaves chiefly radical, long and narrow; half as long 

 as the culm; panicle 3 to 6 inches long, slender, an interrupted spike, 

 at least above, below with short, three to five-flowered, remote, fascicu- 

 late branches; spikelets 1J lines long, plano-convex, obtusish; lower, 

 glume one-half as long as the spikelet, three-nerved, second and third 

 seven-nerved; rhachis terminated by a short bristle, sometimes also a 

 bristle below the spikelets. 



Texas (Eeverchon). 



14. P. subsi)icatum, Vasey. — Culms 10 to 18 inches high, leafy; upper 

 leaves longer than the lower (lowest 1 inch, highest 5 inches), 1 to 

 2 lines wide, rather rigid, light green, acute; panicle spicate at apex, 

 below with five or six short, approximate, appressed, rather lax branches, 

 one-half inch to 1 inch long; spikelets 1 line long, a little curved, 

 lower glume one-half as long as the spikelet, second glume seven-nerved, 

 third glume five-nerved ; rhachis with a short bristle at apex and 

 sometimes a bristle below the spikelets. Leaves shorter and more 

 rigid, spike shorter and closer, and spikelets smaller than in the pre- 

 ceding. 



Texas (Buckley, Nealley). 



These three (12, 13, and 14) form a natural group. 



15. P. stenodes, Gris. (P. anceps var. strictum Chap.).— Culms 2 to 3 

 feet high, wiry, smooth; leaves erect, rigid, narrow (1 to 2 lines), 3 to 

 4 inches long; panicle narrow, 2 to 3 inches long, of five to six slender, 

 short, appressed branches, sessile or nearly so, mostly single, some- 

 times two or three together; spikelets about 1 line long, lanceolate, 

 acute; first glume half as long as the spikelet; second and third five- 

 nerved, acute. In ponds and water. 



Florida to Alabama (Dr. Mohr) aud Texas (Nealley). 



Section IV. — Platyphylla. 



16. P. platyphyllum, Munro. — Culms decumbent and rooting at, the 

 lower joints, 1 to 2 feet high, branching below, pale green in color; 

 leaves lanceolate, 3 to 4 inches long, 4 to 6 lines wide, smooth, firm, 

 the base clasping; margins scabrous, pale green ; sheaths smooth, striate, 

 the upper one inclosing the base of the panicle, which consists of three 

 to five simple, sessile, alternate, slightly spreading, distant branches, 

 each 1J to 3 inches long; spikelets sessile, and alternate on a flat- 

 tened rhachis; lower glume thin, obtuse, one-third as long as the sec- 



