CYPERACEjE. (SEDGE FAMILY.) 501 



meadows, &c., New England to Pennsylvania, Kentucky, Wisconsin, and north- 

 ward. July. (Eu.) 



12. S. polyphyllus, Vahl. Culm, umbel, &c. as in the last; gpikes 

 clustered in heads of 3 - 8, ovoid, becoming cylindrical with age, yellowish-brown ; 

 bristles 6, usually twice bent, soft-barbed towards the summit only, about twice the 

 length of the achenium. (S. exaltatus, Pursh. S. brunneus, MM.) Swamps 

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

 Intermediate in character between the last and the next. 



2. TRICH6PHORUM, Richard. Bristles capillary, tortuous and entangled, 

 naked, not barbed, much longer than the (triangular) acJtenium, when old projecting 

 beyond the rusty-colored scales. (Leaves, involucre, frc. as in the last species.) 



13. S. liiiefitus, Michx. Culm triangular, leafy (l-3high); leaves 

 linear, flat, rather broad, rough on the margins ; umbels terminal and axillary, 

 loosely cymose-panicled, drooping, the terminal with a 1 - 3-leaved involucre much 

 shoiier than the long and slender rays ; spikes oblong, becoming cylindrical, on 

 thread-like drooping pedicels; bristles at maturity scarcely exceeding the ovate 

 green-keeled and pointed scales ; achenium sharp-pointed. Low grounds, W. 

 New England to Wisconsin, and southward. July. 



14. S. Eriophomm, Michx. (WOOL-GRASS.) Culm nearly terete, 

 very leafy (2 -5 high) ; leaves narrowly linear, long, rigid, those of the IHIY>- 

 lucre 3-5, longer than the decompound cymose-panided umbel, the rays at length 

 drooping ; spikes exceedingly numerous, ovate, clustered, or the lateral pedi- 

 celled, woolly at maturity ; the rusty-colored bristles much longer than the pointless 

 scales; achenium short-pointed. (Eriophorum cyperinum, L.) Var. CYPER!- 

 KUS (S. cyperinus, Kunth) is the form with nearly all the spike conglomerate in 

 small heads. Var. LAXUS (S. Eriophorum, Kunth) has the heads scattered, 

 the lateral ones long-pedicelled. Various intermediate forms occur, and the 

 umbel varies greatly hi size. Wet meadows and swamps ; common northward 

 and southward. July -Sept. 



7. EKIOPIIORUItt, L. COTTON-GRASS. 



Spikes many-flowered. Scales imbricated all round in several ranks. Peri- 

 anth woolly, of numerous (rarely 6) flat and delicate hair-like bristles much? 

 longer than the scales, persistent and forming a silky or cotton-like usually white 

 tuft in fruit. Stamens 1-3. Style (3-cleft) and achenium as in Scirpus.- Pe- 

 rennials. (Name from />to, wool or cotton, and ^>opa, bearing.) 



* Bristles of the flower only 6, crisped, white ; spike single : small, involucre none. 



1. E. a I pi till in, L. Culms slender, many in a row from a running 

 rootstock (6' -10' high), scabrous, naked: sheaths at the base awl-tipped. 

 Cold peat -bogs, New England to Penn., Wisconsin, and far northwaid. May, 

 June. (Eu.) 



# # Bristles very numerous, long, not crisped, forming dense cottony heads in fruit. 

 *- Culm bearing a single spike : involucre none : wool silvery white. 



2. E. vagiiifttum, L. Culms in close tufts (1 high), leafy only at the 



