CYPERACE^E. (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; spikes 

 clustered in heads of 3 - S, 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, Muhl.) — Swamps 

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

 — Intermediate in character between the last and the next. 



§2. TRICHOPHORUM, Richard. — Bristles capillary, tortuous and entangled, 

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

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



13. S. laneutUS, Michx. Culm triangular, leafy (l°-3° high) ; 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 

 shorter 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. Eriophorum, Michx. (Wool-Grass.) Culm nearly terete, 

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

 lucre 3-5, longer than the decompound cymose-panicled 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 cyperiuum, L.) — Var. ctperi- 

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

 6mall heads. Var. laxtts (S. Eriophorum, Kunth) has the heads scattered, 

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

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

 and southward. July -Sept. 



7. ERIOPHORUM, 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 eptov, wool or cotton, and (popa, bearing.) 



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



1. E. alpinism, 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 northward. 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. vaginatum, L. Culms in close tufts (1° high), leafy only at the 



