19 
Var. CURTISIANUM (P. Curtisianum Steudel.), larger and stouter; spikes 6 to 8; 
spikelets large; leaves and sheaths hairy.—Florida. 
20, P. pubiflorum Rupr. (P. Hallii Vasey & Scribn., P. remotum Remy(?): Vasey 
in Bull. Torr. Club, xu. 165.) Culms decumbent and branching below, from strong 
creeping rootstocks, leafy, 2 to 3 feet high, stout, nodes (especially the lower ones) 
pubescent; leaves 6 to 9 inches long, 4 to 6 lines wide, scabrous on the margin, acu- 
minate; margin of the sheath ciliate; ligule membranaceous, short; panicle 3 to 4 
inches long, of 3 to 6 spikes; spikes 14 to 3 inches long, firm, dense; rachis broad; 
spikelets in pairs, in 3 or 4 rows, 1 to 14 lines long, oblong, obtuse; empty glumes 
pubescent.—Louisiana to Texas (804 EH, Hall). A form or variety occurs from Arkan- 
sas to Tennessee, which seems to differ only in the smooth glumes of the spikelets. 
Var. GLaucUM Scribn. Another form occurs in Southwestern Texas and Mexico, 
which has more rigid culms aud leaves, is very glaucous, and the spikelets sometimes 
in2rows. (Dr. Havard § C. G. Pringle.) 
21. P. plicatulum Michx. (P. undulatum Poir: Chapm. Fl. 8. States, p. 571.) 
Culms 2 to 3 feet high, rather slender; lower leaves long and narrow, smooth; spikes 
3 to 5, 1 to 2 inches distant, 14 to 2 inches long; rachis narrow; spikelets in pairs, 
mostly in 3 rows, 1 to 1} lines long, oblong oroval, obtuse, plano-convex; empty 
glumes smooth, 3-nerved, the second or flat one becoming plicate or marked with 
linear elevations on the margins; spikelets becoming brown or blackish.—Florida to 
Texas. 
22. P. purpurascens Ell. (Vasey in Bull. Torr. Club, xr. 167.) (Probably P. Bos- 
cianum Fliigge). Culms decumbent below, becoming somewhat erect, 2 to 3 feet long, 
glabrous, branching below (often much branched) ; leaves long (6 to 15 inches), 4 to 6 
lines wide, smooth, except on the glabrous margins, the lower sheaths and culms often 
dark purple; panicle 4 to 6 inches long; spikes 3 to 12, commonly7 to 9 on the main 
culm and 3 to 5 on the branches, 2 to 3 inches long; rachis rather wide, smooth; spike- 
lets in pairs, mostly in 4 rows, about 1 line long, roundish, oval, obtuse.—Florida to 
Alabama. 
23, P. racemulosum Nutt. (Chapm., Fl. 8. States, p.571.) (P. Alabamense Trin, ) 
Culms simple, erect, from strong scaly rootstocks, 2 to 3 feet high; leaves broadly 
linear, flat, mostly fringed on the margins; sheaths hairy or smoothish, purplish be- 
low; spikes, 2 to 4, slender, erect, 3 to 4 inches long; rachis slender, somewhat flexu- 
ous; spikelets rather distant and interrupted, singly or in pairs, distinctly pediceled, 
the pedicel sometimes 3 times as long as the spikelets; spikelets 14 lines long, oblong 
or obovate; empty glumes smooth, 5- to 7-nerved.—Dry sandy soil, North Carolina, 
Florida, and westward to Louisiana, 
24. P. dilatatum Poir. (Vasey in Bull. Torr. Club, x1. 166.) (P. ovatum Trin.) 
Cuims stout, 3 to 4 feet high; leaves 10 to 12 inches long, 4 lines wide, smooth ; spikes 
4 to7, erect or spreading, lax, 2 to 4 inches long; common axis slender; spikelets 
in 4 rows, 14 lines long, ovate, acute, pubescent, villous on the margins; empty 
glumes acute, longer than the fertile flowers.—Virginia to Florida and Texas. 
Var. DECUMBENS. Like the preceding, but only 3 to 4 spikes, and the culms de- 
cumbent or sometimes prostrate.—Louisiana (A. B. Langlois). 
25. P. difforme Le Conte. (Vasey in Bull. Torr. Club, xu. 166.) Culms from 
strong creeping rootstocks, 3 feet high, stout, smooth; leaves rigid, flat, 5 to 6 
-inches long, 3 to 4 lines wide, somewhat scabrous, smoothish or pubescent; panicle 
long, naked below, of 2 to 4 spikes, 1 to 2 inches distant; spikes 14 to 3 inches long, 
thick, firm; spikelets 14 lines long in 2 or 3 rows, ovate-oblong, obtuse, smooth ; 
empty glumes 3-nerved.—North Carolina to Florida (3,570 4. H. Curtiss distribution. ) 
Intermediate between P. leve and P. floridanum. 
26. P. Ploridanum Michx. (Chapm. Fl. 8. States, p. 571.) Culms 3 to 4 feet 
high, erect, rigid; leaves long (1 to 2 feet), 3 to 6 lines wide, hairy or smooth; spikes 
3 to 7, 1 to 2 inches distant, erect, 3 to 5 inches long, thick; rachis rather narrow, 
