CYPERACEAE. 177 



oblong-cylindric, narrowed at each end, several-flowered, 6-10 mm. long, subtended 

 by a subulate erect involucral leaf 1-3 cm. long, thus appearing lateral; scales 

 ovate-lanceolate, acute, membranous, light brown with a green midvein; bristles 

 about 6, downwardly barbed, as long as the achene or shorter; stamens 3; style 

 3-cleft to about the middle; achene obovoid, 3-angled, dark brown, smooth, rather 

 more than 2 mm. long, obtuse, abruptly beaked by the slender base of the style. In 

 ponds and streams or sometimes on their borders, N. B. to the N. W. Terr, and 

 Wash., south to N. J., Penn. and Mich. The so-called variety terrestris is an 

 emersed form with erect culms and shorter spikelets. July-Aug. 



7. Scirpus Hallii A. Gray. Hall's Club-rush. (I. F. f. 615.) Annual; 

 culms very slender, smooth, tufted, obtusely triangular, erect, striate, 1-3 dm. tall. 

 Lower sheaths oblique, and acuminate or mucronate, the upper one commonly 

 bearing a filiform blade 1-6 cm. long; spikelets capitate in clusters of 1-7, oblong- 

 cylindric, obtuse, many-flowered, 6-12 mm. long, about 2 mm. thick, appearing 

 lateral by the extension of the solitary involucral leaf; scales ovate-lanceolate, light 

 greenish brown, acuminate, keeled, cuspidate; bristles wanting; stamens mostly 2; 

 achene obovate -orbicular or slightly broader than high, black, plano-convex, 

 mucronulate, wrinkled transversely, about 1 mm. in diameter. In wet soil, Mass. 

 to Fla., west to 111., Col., Tex. and Mex. The lowest sheaths occasionally subtend 

 a flower with very long styles. July-Sept. 



8. Scirpus debilis Pursh. Weak-stalked Club-rush. (I.F.f. 616.) An- 

 nual, smooth; culms slender, terete or nearly so, tufted, 1.5-5 & m - high- Sheaths 

 obliquely truncate, the upper one rarely bearing a short subulate blade; spikelets 

 capitate in clusters of I- 12, ovoid-oblong, subacute, many-flowered, appearing 

 lateral, the involucral leaf narrowly linear, 3-10 cm. long, erect or divergent; scales 

 light yellowish brown with a green midvein, broadly ovate, obtuse or acute; bristles 

 4-6, downwardly barbed, about as long as the achene; stamens 2-3; style 2-cleft 

 or rarely 3-cleft; achene plano-convex, broadly obovate or orbicular, smooth or 

 slightly roughened, dark brown, shining, obtuse, mucronulate. In wet soil, Me. to 

 Ont. and Minn., south to Ga., Ala. and Neb. July-Sept. 



9. Scirpus Smithii A. Gray. Smith's Club-rush. (I. F. f. 617.) Annual, 

 similar to the preceding species ; culms usually lower and more slender or nearly 

 filiform ; sheaths oblique and acuminate or the upper one bearing a subulate blade. 

 Spikelets 1-4, ovoid, acute, 4-6 mm. long, the involucral leaf narrow, elongated, 

 erect; scales oblong, obtuse, mucronulate, pale brown with a green midvein; 

 bristles usually wanting, sometimes 1-3, and very much shorter than the achene; 

 style 2-cleft; achene plano-convex, obovate or orbicular, brown, rather dull, smooth 

 or minutely roughened, obtuse, mucronulate. In wet muddy places, Vt. to Ont. 

 and Minn., Del., Penn. and Mich. July-Sept. 



10. Scirpus Americanus Pers. Three-square. Chair-maker's Rush. 

 (I. F. f. 618.) Perennial by long rootstocks; culms sharply triangular, erect, stiff, 

 0.3-1. 1 m. tall. Leaves 1-3, narrowly linear, keeled, shorter than the culm; 

 spikelets oblong-ovoid, acute, 8-12 mm. long, capitate in clusters of 1-7, appearing 

 as if lateral; involucral leaf slender, 3-10 cm. long; scales broadly ovate, brown, 

 often emarginate or sharply 2-cleft at the apex, the midvein extended into a subu- 

 late awn sometimes 2 mm. long, the margins scarious; bristles 2-6, downwardly 

 barbed, shorter than or equalling the achene; stamens 3; achene obovate, plano- 

 convex, smooth, dark brown, mucronate. In fresh water and brackish swamps 

 throughout N. Am. Also in Chile. June-Sept. [S. pungens Vahl.] 



Scirpus Americknus longispic&tus Britton. Spikelets linear-cylindric, 1-2.5 cm. 

 long; bristles as long as the broadly obovate achene. S. shore of Lake Ont., Col. and 

 N. Mex. 



11. Scirpus Olneyi A. Gray. Olney's Bulrush. (I. F. f. 619.) Similar to 

 the preceding species; culms stout, sharply 3-angled with concave sides, 0.5-2 m. 

 tall. Leaves 1-3, 2-13 cm. long, or sheaths sometimes leafless; spikelets capitate 

 in dense clusters of 5-12, oblong or ovoid-oblong, obtuse, 5-8 mm. long, the involu- 

 cral leaf short, stout, erect, 1-3 cm. long; scales oval or orbicular, dark brown with 

 a green midvein, emarginate or mucronulate, glabrous; bristles usually 6, slightly 

 shorter than or equalling the achene, downwardly barbed; stamens 2-3; style 

 2 cleft; achene obovate, plano-convex, brown, mucronate. In salt marshes, Mass, 



