564 CYPERACE^E. (SEDGE FAMILY.) 



scales soon recurved ; achenium obovate-orbicular, compressed, flat on one side, con- 

 vex or obtuse-angled on the other, minutely pointed, shining, longer than the 1 -6 un- 

 equal and deciduous (sometimes obsolete) bristles. — Var. macrostachyos, 

 Michx. (S. robustus, Pursh) is a larger form, with very thick oblong-cylindri- 

 cal heads, becoming l'-l^'long, and the longer leaf of the involucre often 

 1° long. — Salt marshes : common on the coast, and near salt springs in the 

 interior (W. New York, &c). (Eu.) 



16. S. fluviatilis, Gray. (River C.) Leaves flat, broadly linear (%' or 

 more wide), tapering gradually to a point, the upper and those of the very long 

 involucre very much exceeding the compound umbel ; rays 5-9, elongated, recurved- 

 spreading, each bearing 1-5 ovate or oblong-cylindrical acute heads ; achenium 

 obovaie, sharply and exactly triangular, conspicuously pointed, opaque, scarcely equal- 

 ling the 6 rigid bristles. (S. maritimus var.? fluviatilis, Ton:, excl. syn.) — 

 Borders of lakes and large streams, W. Vermont to Penn., Wisconsin and 

 Illinois. — Culm very stout, sharply triangular, 3° -5° high. Leaves roughish 

 on the margin, like the last ; those of the umbel 3-7, the largest 1° - 2° long. 

 Principal rays of the umbel 3' -4' long, sheathed at the base. Heads paler 

 and duller than in the preceding ; the scales less lacerate, and their awns less 

 recurved , the fruit larger and very different. 



h- •*- Spikes very numerous, small, V -5" long ; theh scales viucronaie-pointed or 

 blunt : umbel-like cymose panicle irregular, compound or decompound : culm 

 2° -5° high, unusually leafy ; leaves broadly linear, green and rather soft, rough 

 on the edges : bristles of the perianth very slender, often more or less tortuous and 

 naked below: — transition to § Trichophorum. 



17. S. sylv&tiCUS, L. Spikes lead-colortd, clustered. 3-10 together at the 

 end of the mostly slender ultimate divisions of the open decompound panicle, ovoid 

 or lance-ovate, 2" long ; scales bluntish ; bristles 6, downwardly barbed through- 

 out, rather exceeding the triangular short-pointed achenium ; style 3-cleft. — ■ 

 Along brooks, E. Mass., W. Boott, to Albany, N. Y., C. H. Peck. (Eu.) 



18. S. microearpilS, Presl. Like No. 17, but earlier, and with rathef 

 smaller heads, hlunter scales, 2 stamens, a 2-cleft style, 4 bristles, and obovate- 

 lenticular achenium. (S. lenticularis, Ton.) — Near Boston, IV. Boott, to New 

 Hampshire, Oukes, Src, and N. W. 



19. S. atrdvirens, Muhl. Leaves somewhat more rigid ; spikes dull 

 greenish-brown, densely conglomerate (10-30 together) into close heads, these also 

 usually densely clustered in a less compound panicle; scales pointed; bristlec 

 Eparsely and strongly downwardly barbed above the middle, naked below, nearly 

 straight, as long as the conspicuously pointed and obovate-oblong triangular 

 achenium. (S. sylvaticus, var. atrovirens, Ed. 2., — Wet meadows and bogs, 

 New England to Kentucky and northward : common. 



20. S. polyphyllus, Vahl. Culm usually more leafy ; spikes yellow-brown, 

 ovate, becoming cylindrical, clustered 3-8 together in small heads on the short 

 ultimate divisions of the open decompound umbel; scales mucronate; bristles 6, 

 usually twice bent, soft-baibrd towards the summit only, about twice the length of 

 the achenium. (S. exaltatus, Pursh. S. bninneus, Muhl.) — Swamps and 

 shady borders of ponds, W. New England to Illinois, and common southward 



