493 
of perfect spikelet hard, convolute, browu, pubescent; second glume 
softer, the third hyaline, fourth hyaline at base, terminating above in 
iw hard twisted and bent awn: first outer glume of pedicellate spikelet 
lanceolate, green, coriaceous, scarious-margined, many-nerved; second 
glume 38 or 5-nerved, scarious; floral glume and palet hyaline. 
1. H. contortus (L.) R. & 8S. Perennial, strongly rooted, often glaucous: culms 
tufted, smooth, rather slender, branching above, erect, 6 to 9dm. high: leaves flat or 
conduplicate, usually abruptly acute, 3 to6 mm. wide, 1 to 3 dm. long; sheaths cari- 
nate: spikes few, mostly long pedicelled, cylindrical, 6 em. long excluding the awns; 
rachis with a tuft of brown hairs at each node: sessile spikelet dark brown, 7 mi, 
long; awn dark brown below, 6 to 10 em. long: pedicellate spikelet 9 to 11mm. long; 
first gluine subacute, oblique and twisted, (Andropogon contortus L.)—West of the 
Pecos River, 
2, H. melanocarpus (Mulil.) Perennial: culmsrather stout, smooth, bushy-branched 
above, erect, L to 2m. high: leaves flat, attenuate ateach end, Lem. wide, 3 to 6dm. 
long: spikes numerous, approximate, one-sided, 3 to 5 cm, long, shorter than the 
sheathing bract; tufts of hairs on the rachis light brown or white: sessile spikelet 
rusty or dark brown, 8 to 10 mm. long; awn rusty or light brown, 8 to 10 cm, long: 
pedicellate spikelets about 2 em, long; first glume flat, attenuate, wrinkled on the 
back. (Stipa melanocarpa Muhl. Heleropogon acuminatus Trin.)—Eastern Texas to 
Florida, 
7. IMPERATA (Cyrill. 
Panicle spikelike; spikelets in) pairs on unequal short clavate 
articulate pedicels, or one sessile, both perfect, awnless; outer empty 
glumes clothed with long white silky hairs; third and fourth glumes 
and palet hyaline: stamens | or 2: stigmas 2, exserted. 
1. I. Hookeri Rupr. Culms & to 12 dm, high from creeping rootstocks, simple, 
smooth: radical leaves 1 to 8 dm. long; cautine shorter, decreasing upwards; ligule 
short ciliate: panicle nearly cylindrical, erect, 1.5 to 3 dm, long, sometimes interrupted 
below, lower branches 8 to6 dm, long, appressed or slightly spreading: spikelets about 
3imin. long; hairs dense, straight, about 1 em. long, giving the panicle a feathery 
appearance flecked with the yellow or brown anthers and stigmas,—Along water- 
courses, Western Texas. 
8. ERIANTHUS Michx. 
Panicle broad and ample or rarely narrow: spikelets in pairs, one 
sessile and one pedicelled, both alike, 1-tlowered, perfect and awned; 
outer empty glumes nearly equal, coriaceous, 5 to 7-nerved; 3d and 4th 
elunes and palet membranaceous, often bright red or purple, the 4th 
awned: stamens 2: styles distinct; stigmas 2, slightly exserted: tall 
reed-like perennials with large coarse leaves more or less pubescent. 
* Tuft of silky hairs at the base of each spikelet. 
1. BE. alopecuroides (L.) Ell. Culms 1 to 2 m. high, hairy at the nodes: panicle 
densely flowered, 1.5 to 3 dm. long and half as wide; axis silky villous: spikelets 5mm, 
long, shorter than the hairs; outer glumes and pedicels sparsely hairy; awn nearly 
straight, 1 to 2cm. long. (E. saccharoides Michx.)—New Jersey to Texas, Mexico, 
and South America. 
2, EB. brevibarbis Michx. Culms 1 toi.5 m. high, rather stiffly bearded at the 
upper nodes: panicle 1.5 to 3. dm, long, less dense than the preceding; axis pubescent 
or smooth: spikelets 6 to 7mm. long, equaling or exceeding the hairs at the base; 
