CYPERACEAE (SEDGE FAMILY) 



191 



286 S americanus 



1-5 ovoid acutish spikelets (0.5-1 cm. long); involucral leaf always 

 erect ; scales oblong-oval ; style 2-cleft ; bristles I or 2 minute 

 rudiments or none ; acbene cuneate-obovate. Wet shores, local, 

 Me. to Pa., 111., Mich., and Out. July-Sept. FIG. 285. Var. 

 SETOMS Fernald. Perianth of 4 or 5 slender retrorsely barbed 

 bristles, mostly exceeding the achenes. Me. ; 

 Mass. ; and 111. 



12. S. americanus Pers. Running rootstocks 

 long and stout ; culms sharply 3-angled through- 

 out (0.2-1 m. high) with concave s.des ; leaves . 

 1-3, elongated (1-8 dm. long), keeled and chan- 

 neled ; involucral leaf pointed ; spikelets 1-6, capitate, ovoid, 

 mostly 0.5-1 cm. long ; scales ovate, sparingly ciliate, 2-cleft 

 at the apex ; anthers tipped with an awl-shaped minutely fringed 

 appendage; style 2-cleft (rarely 8-cleft); bristles 2-0, shorter 

 than the smooth achene. (S. pungens Vahl.) Borders of 

 ^ and fresh P onds and streams, temperate N. A. Aug.- 

 Oct. (Eu., S. A.) FIG. 286. 

 13. S. Torr&yi Olney. Rootstocks slender and weak; culm %-angled, with 

 concave sides, rather slender (0.4-1.5 m. high), leafy at base ; leaves 2 or 3, more 

 than half the length of the culm, triangular-channeled, slender ; 

 involucral leaf blunt; spikelets 1-4, oblong or spindle-shaped, 

 acute, distinct, 1-1.5 cm. long; scales ovate, smooth, barely mu- 

 cronate ; style 3-cleft ; bristles longer than the unequally triangular 

 very smooth long-pointed achene. Borders of ponds, brackish 

 and fresh, Me. to Pa., la., and Man. Aug., Sept. 

 FIG. 287. 



14. S. Olnfcyi Gray. Culm B-wing-angled, with 

 deeply excavated sides, stout (0.5-2 m. high), the 

 upper sheath bearing a triangular leaf or none; 

 spikelets 6-12, closely capitate, ovoid, obtuse, over- 

 topped by the short involucral leaf ; scales orbicular, 

 smooth, the inconspicuous mucronate point shorter 

 than the scarious apex ; anthers with a very short and blunt 

 minutely bearded tip ; style 2-cleft ; bristles 6, scarcely equaling 

 the narrowly obovate plano-convex and mucronate achene. Salt 

 i marshes, N. H. to Fla. ; also in Mich., and on the Pacific coast. 

 July-Sept. (W. I.) FIG. 288. 



15. S. MUCEONA.TUS L. Resembling the last, 3-9 dm. high ; involucral leaf 

 divergent; spikelets numerous in a dense cluster, oblong-ovoid; scales ovate, 

 mucronate, firm, scarcely at all scarious; style 3-cleft; 



achene unequally trigonous, broadly obovate. In a 

 single locality in Delaware Co., Pa.; probably introd. 

 from s. Eu. 



16. S. etuberculatus (Steud.) Ktze. Culm (1-2 m. high) 

 3-angJed, usually sharply so above, obtusely below, the 

 sheath at base extended into a long slender triangular and 

 channeled leaf; involucral leaf similar (1-2.5 dm. long), 

 continuing the culm ; spikelets cylindric (1-2 cm. long), 

 single or sometimes proliferously 2 or 3 together, nodding 

 on the apex of the 5-9 long filiform and flattened peduncles 

 or rays of the dichotomous umbel-like corymb, or the 

 central one nearly sessile ; scales loosely imbricated, 

 oblong-ovate, acute, pale, thin and scarious, with a green- 

 ish nerved back; bristles 6, firm, furnished above with 

 spreading hairs rather than barbs, equaling the slender 

 abrupt beak of the obovoid-triangular shining achene 

 (4 mm. long). (S. Canbyi Gray ; S. cylindricus Britton.) 

 -Swamps and ponds, Md. to Fla., etc. June-Aug. 



FIG. 289. 889. 8. etuberculatus. 



g Torreyi 



