548 GRAMINEJ. (GRASS FAMILY.) 
48, AMPHICARPUM. Spikelets of two kinds ; one disposed in a terminal panicle, perfect but 
seldom fruiting ; the other fruitful, on long solitary radical peduncles. 
* * Glumes 2, the lower one often minute, rarely wanting. 
49. PANICUM. Spikelets single, without a bristly or spiny involucre. 
50. SETARIA. Spikelets crowded in spike-like panicles, subtended by a bristle-like involucre. 
51. CENCHRUS. Spikelets single, or few in a cluster, enclosed in an indurated and spiny in- 
voluere. Spikelets spiked. 
52. STENOTAPHRUM. Spikes and spikelets mostly as in Rottboellia, but the flowers as in 
Panicum. à 
Tusz IX. ROTTBOELLIACEJE. — Spikelets 1-2-flowered, by pairs, imbedded in 
an excavation of the thick and jointed rachis, one stalked and imperfect, the other sessile 
and perfect; or the upper spikelets all staminate and the lower pistillate. Lower glume 
€oriaceous or cartilaginous. Pales awnless. 
53. ROTTB(ELLIA. Spikelets 2 on each joint, one stalked and sterile, the other sessile and 
perfect, 
54. MANISURIS. Spikelets 2 on each joint, the one at the top of the joint sterile, the other 
at the base globose and fertile. 
55. TRIPSACUM. Upper spikelets by pairs, all staminate ; the lower ones single, and pis- 
tillate. ; 
Tu»; X. ANDROPOGONEUX. — Spikelets 2-8 on each joint of the slender hairy or 
plumose rachis. Glumes more rigid than the thin-awned pales. 
56. ANDROPOGON. Spikelets 2 on each joint of the plumose or hairy rachis, one sessile and 
perfect, the other stalked and imperfect or rudimentary. ; 
57. ERIANTHUS. Spikelets 2 on each joint of the rachis, both fertile and surrounded by 8 
hairy involucre. 
58. SORGHUM. Spikelets panicled, 2-3 together, the lateral ones rudimentary. 
l LEERSIA, Swartz Farse Rice. 
Perennial aquatic or marsh grasses, with the leaves and sheaths roughened 
with minute recurved points, the 1-flowered (whitish) spikelets crowded in 
leided panicled racemes. Pedicels jointed. Glumes none. Pales 2, charta- 
ceous, strongly compressed, fringed on the keel, the lower one much wider. 
‘Stamens 1—6. Stigmas 2. Grain compressed. sy 
1. L. oryzoides, Swartz. Panicle large, diffuse; spikelets oblong, flat, 
loosely imbricated ; stamens 3. — Ditches and swamps, Florida, and northw 
July and Aug. — Culm 3? - 4? long, commonly prostrate at the base. Jr 
spreading. Base of the panicle mostly enclosed in the sheath of the subtending 
leaf. Spikelets strongly fringed, about 3" long. oe 
2. L. Virginica, Willd. Panicle nearly simple, the lower branches spread- 
a, and 
2 ing; spikelets small, concave, sparingly fringed, closely imbricated; § 
northward. July and Aug. — More slender than the last, and with spikelets 
go FPE. 
. Michx. Panicle diffuse ; spikelets oval, flat, A qun 
ed; stamens 2. — Ponds and swamps, Florida 60 7 a. 
