SciRPUs. CLX. CYPERACEiE. 571 



almost capillary, 2 — if lonpf ; sjrikc solitary, somewhat terminal (the stem being 

 continued above it in tlje form of a bract), lanceolate ; slijle 2-cleft ; bristles 6. — 

 Streams, &c., Mass. ! to N. Y. Aug. 



3. S. ca;spitosus. Bractcd Mountain Rusk. 



Sfs. cocspitose, round, sheathed at base with numerous rudiments of leaves ; 

 spikes coinpressfd, terminal ; "2 lower ^lu/ius involucre-like, as lonj^ as the sj)ike; 

 ach. with 6 bristles. — Grows in den.se tufts, 4 — 12' high. Spike 4 — 5-llowered, 

 reddish-brown. On the White Mts., N. H., Bio. July. 



4. S, RoBBiNsii. (auct.?) 



St. 12 — 18' high, soft, loosely cellular, terete, leafy at base; Irs. submersed, 

 shorter than the stems, very narrowly linear, loosely cellular; s/;/A'e broad-ovate, 

 3 — 4" long, placed about G" below the apex of the stem ; glumes loose, 10 — 13, 

 ovate, acute, green ; bristles 3 — 6, shorter than the achenia; arh. globose-ovoid, 

 biconvex, smooth, of a dull brown, with a slender, conspicuous beak. — Pond.s, 

 Oxbridge, Mass., Dr. Bobbins I 



* * Spikes vianij^ lateral. 



5. S. DEBiLis. Pursh, Weak-stemmed Rvsh. 



St. caespitose, roundish, deeply striate, 9 — 16' high, with a few subulate 

 leaves at base ; spikelcts about 3, short-ovoid, sessile, crowded, subterminal ; 

 glumes ovate, obtuse, carinate, pale green; ach. obovate, mucronate ; bristles 4 — 

 5. — Borders of ponds and rivulets, N. Eng. to Car. Aug. 



6. S. TRidUETER. Michx. (S. Americanus. Pers.) Three-cornered Rush. 

 St. nearly naked, 3-angled, corners acute and two of the sides concave, 



about 3f high "and ending in a sharp point ; Ivs. few and short, from the top of 

 the sheath ;"5;nAc5 lateral, 1 — 5, ovate, crowded and sessile, at various distances 

 below the point ; glumes round-ovate, mucronate ; bristles 6. — Ponds and marshes, 

 fresh and salt, throughout N. America. 



7. S. LACCSTRis. (S. acutus. Muhl.) Lake Bvllrush. 



Scape smooth, leafless, filled with a porous pith, 5 — 8f high, cylindric, 

 tapering above the panicle, and abruptly ending in a short cusp ; panicle cymose 

 near the top ; pe^^. rough, twice compound; spikelets ovoid, closely imbricate; 

 scales ovate, mucronate, pubescent; bracts shorter than the panicle. — The largest 

 species of buUrush, frequenting the muddy margins of rivers and ponds U. S. 

 to Arc. Am. July. 



8. S. Olneyi. a. Gr. Olnci/s Rusk. 



St. triquetrous-winged, leafless, 2 — 7f high ; sheath radical, tipped with a 

 short (1—2') leaf; spikes 6 — 12, sessile, aggregated, 2—3" long, placed 9—12" 

 below the triangular apex of the stem ; glumes roundish-ovate, mucronate ; 

 bristles 6 — 12; ack. obovate, plano-convex, gibbous at apex. — Salt marshes, 

 Sekonk river, R. I., Ohiey ! Tom river, N, Y., Kneiskern. Remarkably distin- 

 guished by its 3- winged stem. July. See also Addenda, p. 638. 



* * * Spikes terminal. 



9. S, MARiTiMUS. Sea Bullrusk. 



St. acutely 3-angled, leafy, 2 — 3f high; Ivs. broad-linear, rough-edged, 

 carinate, taller than the stem; spikes conglomerate, 6 — 10, nearly an inch long, 

 corvmbose; invol. of about 3 very long leaves; glumes ovate, 3-cleft, the middle 

 segment subulate and reflexed; style 3-cleft; bristles 3 — 4, much shorter than 

 the broad-obovate, lenticular, dark brown, polished achenium. — Salt marshes, 

 N. Eng. ! to Flor. Aug. 



fi.Jluviatilis. Torr. Umbel somewhat compound; bristles 6, as long as the 

 obovate, triangular, dull grayish achenium. — Fresh water swamps and lakes, 

 Western N. Y. to Wis., Laphavi! and Mo. 



10. S. ATROVlRENS. Muhl. 



St. obtusely triangular, leafy, 2f high ; cyme compoimd, proliferous ; invol. 

 of 3 leaf-like bracts, longer than the cyme ; spikes ovate, acute, crowded, 10 — 20 

 in a globose head; hds. numerous, |' diam., dark green ; glumes ovate, mucro- 

 nate ; ack. white, smooth ; bristles 4:. — Common in meadows^ Middle and Western 

 States. June, July. 



