A474 
* * Style deeply bifid. 
+ Bristles none or rudimentary. 
3. R. nitens Gray. Stems nearly terete, 1.5 to 6 dm. high: leaves narrowly 
linear, longer than the stem: corymbs 2 or 3, widely spreading, the terminal one 
mostly compound: spikelets ovate, many-flowered, all the scales (ovate, acute) with 
perfect flowers: achene lenticular, orbicular, strongly transversely wrinkled; tuber- 
cle compressed, very short. (Scirpus nitens Vahl. Psilocarpa rhynchosporoides Torr. 
P. Texensis Torr, & Hook.)—Extending into Texas from the south Atlantic and Gulf 
States. 
4. R. pusilla Curtis. Stems (15 to 30 em. high) and leaves bristle-form: corymbs 
2 or 8, distant, spreading, the upper one compound: spikelets minute, ovate, mostly 
scattered on the branches, 1 to 3-flowered: scales ovate, brown: achene white, 
oblong-obovate, compressed-lenticular, contracted at base, transversely wrinkled ; 
tubercle depressed-conical.—A West Indian species, extending through the Gulf 
States to Texas, 
+ + Bristles 6, plumose. 
5. R. oligantha Gray. Stems (15 to 30 em. high) and smooth leaves bristle-like, 
reclining: corymb terminal, of 3 to 6 large ovate-lanceolate whitish stalked spike- 
lets: bristles plumose below the middle, longer or shorter than the oval lenticular 
faintly wrinkled achene: tubercle dilated at base, conical, tlat.—From the south 
Atlantic and Gulf States to Texas. 
6. R. plumosa Ell. Stems (15 to 30 em, high) and leaves filiform: spikelets few, 
in about 3small clusters at the summit of the stem: bristles plumose throughout or 
nearly to the summit, rather longer than the nearly globular strongly wrinkled 
achene which is pointed with the short ovate smooth tubercle.—Extending into 
eastern Texas from the south Atlantic and Gulf States. 
7. R. intermedia Britton. Stems taller (3 to 6 dm.) and leaves narrowly linear: 
spikelets in clusters of 4 to 6, forming an interrupted spike at the summit of the 
stem: bristles plumose only at base or below the middle: achene obovate, lenticular, 
pointed with the conical-beaked pubescent tubercle. (2. plumosa var. intermedia 
Chapm.)—A Florida species, but reported from near Sabine Pass, 
8. R. semiplumosa Gray. Stems erect, rigid, 3 to 6 dm. high: leaves narrowly 
linear: spikelets oblong-ovate, dark brown, crowded in a terminal head, or rarely 
ina remote axillary one: bristles exceeding the tubercle, plumose below the middle: 
achene globose-obovate, faintly wrinkled, pointed with the short broadly conical 
smooth tubercle.—From Florida to Texas. 
+ + + Bristles retrorsely barbed. 
9, R. alba Vahl. Stems slender, 3 to 6 dm. high, triangular above: leaves nar- 
rowly linear or almost bristle-form: spikelets lanceolate, white or whitish (tawny 
with age), perfecting only a single flower, densely crowded in a head-like terminal 
corymb and usually 1 or 2 lateral ones: achene oblong-obovate with narrowed base, 
scarcely longer than the flattened awl-shaped tubercle, shorter than the 9 to 12 
bristles.—Across the continent north of our range, but represented in Texas (Drum- 
mond) by the var. MACRA Clarke, in which the clusters are larger (sometimes 3 em. 
broad), and the bristles more numerous (15 to 20). 
10. R. glomerata Vahl. Stem 3 to 9 dm. high: leaves linear, flat: spikelets 
numerous in distant clusters or heads (often in pairs from the same sheath), ovoid- 
oblong, dark chestnut-brown, few to-several-flowered: achene obovate, margined, 
narrowed at base, as long as the lance-awl-shaped flattened tubercle, which equals 
the usually 6 bristles.—Throughout eastern United States and extending into Texas. 
Var. PANICULATA Chapm. (i. paniculata Gray), of the south Atlantic and Gulf 
States, has stouter taller stems, and compound paniculate corymbs with the very 
numerous spikelets clustered at the summit of the branches, 
