471 
* Spikelet solitary (sometimes 2), sessile, terminal or lateral, 
1. S. nanus Spreng. Stems very slender, bristle-like, flattened and grooved, 2.5 
to5em. high: spikelet solitary and terminal, ovate, 3 to 8-flowered: scales ovate 
and greenish, the upper rather acute: bristles mostly longer than the fruit: achene 
ovoid, acutely triangular, smooth and shining, minutely tipped. (Hleocharis pygmeaa 
Torr.)—Salt-marshes, from the north Atlantic coast to Texas. Var. ANACHATUS 
Britton, extending from Louisiana to New Mexico and Mexico, is a form without 
bristles, 
2. S. carinatus Gray. Stems slender, triangular and channelled, 2.5 to 10 em. 
high, with a short leaf at base: spikelets 1 or 2, subtended by a single erect invol- 
ucral leaf, 5 to 10-flowered: scales very broadly ovate, greenish or tinged with brown, 
strongly keeled and boat-shaped, acute, gibbous in fruit and retaining the brown 
achene, which is very road, acutely triangular, smooth, with a broad scar at 
summit: bristles none.—In low ground, extending from the Gulf States into Texas. 
** Spikelets several or numerous, capitate or umbelled, subtended by one or several involu- 
cral leaves. 
+ Spikelets appearing lateral, the 1-leaved involucre appearing to be a continuation of the 
naked stem. 
3. &. Hallii Gray. Stems filiform, 12.5 to 30 cm. high, upper sheath rarely dis- 
tinctly leaf-bearing: spikelets 1 to 7 in a sessile or sometimes proliferous cluster, 
ovate-oblong becoming cylindrical: scales ovate, greenish, strongly keeled, mucro- 
nate-pointed: bristles none: achene obovate-orbicular, mucronate, plano-convex, 
strongly wrinkled transversely. (8. supinus, var, Halliit Gray.)—Throughout east 
United States, and extending through Texas into Mexico. 
4. S. Americanus Pers. Stems stout, sharply triangular throughout with con- 
cave sides, 3 to 12 dm. high, from long and stont running rootstocks: leaves 1 to 8, 
elongated (10 to 25 em.), keeled and channeled: spikelets 1 to 6, capitate, ovoid, 
much overtopped by the pointed involucral leaf: scales ovate, rusty-brown, spar- 
ingly ciliate, 2-cleft at apex and awn-pointed from between the acute lobes: anthers 
tipped with an awl-shaped minutely fringed appendage: bristles 2 to 6, shorter than 
the obovate mucronate smooth achene. (8. pungens Vahl.)—In salt or fresh marshes 
and low grounds throughout North America. 
5. §. Olneyi Gray. Stem stout (6 to 20 dm, high), 3-wing-angled, with deeply 
concave sides, the upper sheath bearing a short triangular leaf or none: spikelets 
6 to 13, closely capitate, ovoid, obtuse, overtopped by the short involucral leaf: 
scales orbicular, rusty-brown, smooth, the inconspicuous mucronate point shorter 
than the scarious apex: anthers with a very short and blunt minutely bearded tip: 
bristles 6, scarcely equaling the narrowly obovate mucronate achene.—In salt 
marshes, from the north Atlantic States to the gulf and extending westward through 
Texas to Mexico and the Pacific coast. 
6. S. lacustris L. Stem terete, very tall (9 to 36 dm.) and stout, from a deep run- 
ning rootstock, leafless or nearly so: spikelets numerous, ovate-oblong, clustered in 
a one-sided compound umbel-like panicle longer than the involucral leaf: scales 
rusty or chestnut-brown, scarious, mostly a little downy on the back and ciliate, the 
midrib extended into a mucronate point: achene pale and dull, obovate with a nar- 
rowed base, mucronate-pointed, usually overtopped by the 4 to 6 slender down- 
wardly barbed bristles. (8. validus Vahl.)—In ponds and streams throughout North 
America. Known as the “ great bulrush” or “tule” and sometimes occupying large 
areas in marshy ground. 
7. S. Californicus Britton. Very near the last, but distinguished by the 2 to 4 
very dark-brown bristles which are somewhat flattened and retrorsely plumose with 
short curved hairs and shorter than the achene, which is narrowly obovate and 
