CYPERACEAE I 65 



Bristles downwardly barbed; spikelets in umbelled heads. 

 Bristles equalling or slightly exceeding the achene. 

 Style 3-cleft; achene 3-angled; bristles 6. 



Spikelets 3-8 in each head; bristles barbed 



throughout. 15. 5. sylvaticus. 



Spikelets 8-20 in each head; bristles not barbed 



below. 16. 5. atrovirens. 



Style 2-cleft; achene plano-convex; bristles 4. 17. 5. microcarpus. 



Bristles flexuous, twice as long as the achene. 18. 5. polyphyllus. 



Bristles smooth or slightly pubescent; umbel mostly decom- 

 pound. 

 Bristles shorter than or scarcely exceeding the scales. 19. S. lineatus. 

 Bristles much exserted beyond the scales when mature. 20. 5. cyperinus. 



1. S. nanus Spreng. (S. parvulus R. & S. and Eleocharis pygmaea 



Torr.). Muddy places in salt marshes: Cape Breton Is. to 

 Fla. and Tex. and about the salt springs in N. Y., Mich, and 

 Minn. Also on the Pacific Coast; in Africa, Cuba and Mex. 

 Throughout our coastal marshes, but not reported from Pa. 



2. S. planifolius Muhl. In woods and thickets: Vt. and Mass. 



to Del., D. C, western N. Y. and Mo. 



Conn. Throughout. 



N. Y. Rare and local on L. I., frequent on S. I. and in the 



Bronx, thence increasing northward. 

 N. J. Rare in Gloucester Co., west of the pine-barrens; Mercer 



Co., thence increasing northward. 

 Pa. Throughout, increasing northward. 



Tertiary, O: Cretaceous, rare: Older Formations, increasing 

 northward. 117-220 days. Sea-level-3,800 ft. 



3. S. subterminalis Torr. In ponds and streams or on their 



edges: Newf. to N. W. Terr, and Br. Col., S. Car., Pa., Mich, 

 and Idaho. 



Scattered throughout the range, and common in the pine-barren 

 streams; unknown on S. I. 



4. S. debilis Pursh (S. Smilhii A. Gray and S. Smithii setosus 



Fernald). In wet soil: Me. to Ont., Minn., Ga., Ala. and 



Neb. 



Conn. Throughout. 



N. Y. Throughout, increasing northward. 



N. J. Rare and local in Salem, Monmouth and Camden counties, 



