690 : CYPERACEAi SCIRPUS 
ning rootstocks, 6 inches to 2 feet high, somewhat flattened above, leafy: 
leaves nearly equalling the stem, deeply channelled or revolute, very rough 
on the margins, sharply acute: spikelets 1-8, in a sessile cluster; ovate-oblong, 
«acute, 4-10 lines long: scales brown and shining, ovate, sharply carinate, 
acutish; bristles 1-3, not half the length of the achene: style 2-cleft: achene 
broadly ovate, plano-convex, acute, a linelong. In alkaline soil on borders 
of lakes, eastern Oregon to Nevada and California. 
’ §.° lacustris L. Sp. 48. Perennial by stout rootstocks: stems stout, 
terete, 6-12 feet high, often nearly an inch in diameter, sheathed below, the 
the upper sheath sometimes extended into a short leaf: involucral bract stout, 
shorter than the inflorescence: spikelets numerous, solitary or more or less 
clustered in an irregularly compound umbel, oblong-ovate, 3-6 lines long: 
scales broadly ovate, very obtuse toemarginate and mucronate, ciliate, often 
pubescent, usually pale with fine brown lines; bristles usually 6, slender, 
equalling or longer than the achene; stamens 3, style 2-cleft; achene broadly 
obovate, rounded at the summit, abruptly short beaked. In marshes, Alaska 
to California and the Atlantic States; also in Europe. 
+ + Stems acutely triangular or triquetrous. 
S. Olneyi Gray Bost. Journ. Nat. Hist. v, 238. Stem stout, 2-7 feet 
high, from a stout running rootstock; more or less deeply triquetrous or 
wing-angled, sheathed at base; leafless or with a few short leaves; involucral 
bract stout. triangular, an inch or less longer than the inflorescence; spikelets — 
2-12, in a crowded sessile cluster, oblong-ovate, brown: bristles 4-6, shorter 
than or equalling the achene: stamens 2° or 3; style 2-cleft: achene obovate, 
plano-convex, mucronate, brown. In salt marshes, eastern oregon to Cali- 
fornia and the Eastern States. ; 
S. Americanus Pers. Syn. i, 68. S. pungens Vahl. Stems usually 
slender, from long perennial rootstocks, 1-4 feet high, acutely triangular, 
somewhat leafy at base: leaves 1-4, shorter than the stem, keeled; involucral 
bract more or lesschannelled, 1-4 inches long: spikelets 1-6, closely crowded 
in a sessile cluster, ovate to ovate-oblong: scales brown, often very dark, 
broadly ovate, emarginate and usually tipped with a straight awn: bristles 
2-6, shorter than or equalling the ncliesine stamens 3: style usually 2-cleft: 
achene obovate, smooth, dark brown mucronate. Common in salt marshes, 
throughout the United States. 
* * * Stems triangular, leafy at base: leaves flat: involucre foliaceous. 
Spikelets large, few, in a sessile cluster or sparingly umbellate, rufous. 
S. robustus Pursh Fl. 56. Stems stout, 1-3 feet high, from running 
often tuberiferous rootstocks: leaves flat, equalling or exceeding the stem: 
involucral bracts: unequal, one much longer and more erect: spikelets ovate 
to oblong-ovate, acute, 5-10 lines long: scales ovate, 2-3 lines long, dull 
brown, emarginate, tipped with a long slender soon reflexed awn: bristles 
1-6, fragile, shorter than the achene: stamens 3: style 3-cleft: achene com- 
pressed very flat on the face, convex, or with a low. ridge on the back, 
obovate-orbicular, dark brown, shining, 1} lines long. In salt marshes, 
Bri. Columbia to California and the Atlantic States, 
+ + Spikelets small, numerous, greenish or light brown, ina 
compound or decompound umbellate panicle. 
‘-$. microcarpus Pres]. Reliq. Henk. i, 195. S. sylvaticus var. digynus 
Bekl. Stems usually stout, 3-5 feet high, from perennial rootstocks: 
leaves ample, often exceeding the stem, rough-margined, those of the in- 
volucre usually exceeding: the inflorescence: panicle ample, decompound, 
rather loose: spikelets ovoid, oblong, acute, 144-2 lines long, 3-25 together 
