564 CYPEEACE^. (sedge family.) 



scales soon recurved ; achenium 6bovate<frhicular, ccmipressed, Jiat 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. macrostAchtos, 

 Michx. (S. robiistus, Pursh) is a larger form, with very thick oblong-cj'lindri- 

 cal heads, becoming I'-lJ' 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. fluvi^tilis. Gray. (Ritek C.) Leaves fiat, 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 

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

 ling the 6 rigid bristles. (S. raaritimus var.? fiuviatilis, Torr., 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. 



•I- ■<- Spikes very numerous, small, 1 ' - 3' long ; their scales mucronate-pointed or 

 blunt : umbel-lihe 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^tieus, L. Spikes lead-colored, clustered 3-10 together at the 

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

 (Ij" long) ; the scales blunt or barely mucronate; bristles 6, downwardly barbed 

 their whole length, straight, scarcely longer than the convex-triangular short- 

 pointed achenium. — Base of the White Mountains, New Hampshire {Oakes), 

 and northward. (Eu.) (S. microoAkpus, Presl., S. lenticularis, Torr., appar- 

 ently a form of S. sylvaticus with a 2-cleft style and flat achenium, approaches 

 our northwestern borders.) 



18. 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 ; bristles 

 sparsely 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. 



19. S. polyph^^Uus, Vahl. Culm usually more leafy ; spikes yellow-brown, 

 ovate, becoming cylindrical, clusle'-:a 3-8 together in small heads on the short 

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

 usually twice bent, sofl-barbed towards the summit only, about twice the length of 

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

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

 rare at the North. 



