110 CYPERACEAE 



spikelets 1-4, capitate, oblong-cylindric, acute, 5-12 mm. long; glumes ovate, 

 cusijidate-acumi.iate, with pale brown margins; style 3-cIeft. Wet places: Tex. 

 — Wyo. — -Utah — -Mex. Plain — Subinont. 



8. S. americanus Pers. Stems erect, 3-12 dm. high; leaves 1-3, narrowly 

 linear, keeled; spikelets 1-7, oblong, acute, 8-25 mm. long; bract 2-10 cm. long; 

 glumes broadly ovate, brown, often emarginate or 2-cleft, awned ; achenes smooth, 

 dark brown. S. punjens Vahl. Fresh or saline swamps: Newf. — Fla. — -Tex. 

 —Calif.— B.C. PlainSuhmonl. Je-S. 



9. S. Olneyi A. Gray. Stems stout, 6-20 dm. high; leaves 1-3, narrow, 2-12 



cm. long; spikelets 5-12, oblong, obtuse, 5-8 mm. long; bract short, stout, 1-4 

 cm. long; glumes oval or orbicular, dark brown, with green midrib, emarginate 

 or mucronate, brown. Salt marshes: N.H. — Fla. — -Tex. — -Calif. — Ore.;W. Ind.; 

 Mex.; C. Am. Plain — -Son. Je-S. 



10. S. nevadensis S. Wats. Stems 2-4 dm. high; leaves several, mostly 

 basal, convolute; spikelets 1-5, ovoid or ovoid-oblong, 6-18 mm. long; bract 

 flattened above, rough-margined; glumes broadly ovate, obtuse or acute, chest- 

 nut-brown, smooth and shining; achenes minutely reticulate. Wet places, 

 especially in alkaline soil: Sask. — -Wyo. — Calif. — -Wash. Son. Je-Jl. 



11. S. validus Vahl. Stems stout, terete, smooth, spongy, 1-3 m. high, 

 sometimes 2 cm. thick, sheathed below; spikelets 5-12 mm. long, 3-4 mm. thick; 

 glumes ovate or suborbicular, slightly pubescent, with strong midrib; achenes 

 plano-convex. S. lacustris Am. auth., not L. Common Bulrush. In water: 

 Newf.— Fla.— Calif.— B.C.; W. Ind.; Mex. Plain— Mont. Je-S. 



12. S. occidentalis (S. Wats.) Chase. Similar to S. valilus; basal sheaths 

 fimbrillose on thf margins; spikelets 20 mm. long, 4 mm. thick; glumps ovate, 

 short -awned, viscid above; achenes biconvex. S. lacustris occidenta'is S. Wats. 

 TuLE. In water: Newf.— N.Y.— Mo.— N.M.— Calif.— B.C. Plain— Suhmont. 

 Jl-S. 



13. S. heterochaetus Chase. Similar to S. ra'idus: stem slender, 1-2 m. 

 .high, sheathed below; bracts glabrous; spikelets usually solitary on the slender 

 branches, ovoid or ellipsoid, acutish, 8-15 mm. long, about 5 mm. thick; glumes 

 ovate, glabrous, often erose-margine 1. In water: Vt. — -Mass. — Neb. — Ida. — 

 Ore. Jl-S. 



14. S. paludosus A. Nels. Stems slender, smooth, sharply triangular, 3-6 

 dm. high; leaves pale green, smooth, 2-4 mm. wide; bracts 2 or 3; spikelets 

 oblong-cylindric, mostly acute, 15-25 mm. long; glumes ovate, puberulent or 

 glabrous, pale brown, 2-toothed at the apex, awned; achenes lenticular, obovate, 

 yellowish brown. S. campestris Britt., not Roth. S. interior Britt. S. Brit- 

 tonianus Fiper. Salt marshes: Que. — N.J. — -Kans. — -Tex. — -Calif. — Wash. Plain 

 — Submont. My-Au. 



15. S. microcarpu? Presl. Stem 1-1.5 m. high; sheaths often tinged with 

 red; leaves rough-margined, often 1 m. long or more; spikelets ovoid-oblong, 

 acute, 3-4 mm. long; glumes brown with green midvein; stamens 2; achenes 

 oblong-obovate, nearly white. S. rubrotinctus Fern. Swamps: Newf. — Conn. 

 —N.M.— Calif.— Alaska. Plain— Submont. Jl-S. 



16. S. atrovirens Muhl. Stem tri.uigular, leafv, 6-14 dm. high; leaf -blades 

 elongate, more or less nodulose, rough on the margins, dark green, 6-12 mm. 

 wide; spikelets ovoid-oblong, acute, 4-10 mm. long; glumes greenish brown, 

 ovate-oblong, acute; bristles rarely wanting. Swamps: N.S. — -Ga. — N.M. — -La. 

 — Sask. Plain — -Submont. Je-Au. 



17. S. pallidus (Britton) Fernald. Stem triangular, 1-1.5 m. high; leaf- 

 blades elongate, pale, 6-15 mm. wide, somewhat nodulose; spikelets oblong to 

 oblong-cylindric; glumes pale, ovate, acute, tipped with an awn half as long as 

 the body. Wet ground: Man. — Kans. — Tex. — N.M. — -Wyo. Plain — Submont. 

 Je-Au. 



18. S. cyperinus (L.) Kunth. Stem smooth, obtusely 3-angled or nearly 

 terete, 6-18 dm. high; leaf-blades elongate, 4-6 mm. wide, rough-margined; 

 bracts 3-6, their bases often brown or black; umbels irregularly compound; 



