CAREX. CLX. CYPERACE.E. 577 



A. Spike single. 2. Dioecious. 



2. C. DAVALLIANA. Smith. 



Spike oblong, rather loose-flowered; perig. ovate-lanceolate, attenuate, 

 convex, terete, recurved, longer than the ovate glume ; st. and Ivs. are usually 

 serrulate. Wayne Co., N. Y., Sartwell. 



3. C. EXILIS. Dewey. 



Fertile spike J* below, ovate, rather densely-flowered ; perig. ovate-lanceo- 

 late, convex on both sides, diverging, serrulate on the margin, a little longer 

 than the ovate, acute glume ; Ivs. setaceous ; st. 12 20' high. Grows in Dan- 

 vers and Ipswitch, Ms., Oakes, in N. Y. and N. J. May. 



/?. squamacea. Dew. Spike often an inch long, having many <$ glumes at the 

 base and few perig. at the summit. Longer than the other, and grows with 

 it in Ipswich, Mass., Oakes. 



B. Spikes several* androgynous. 

 1. Stamens variously situated above, below, or in the middle ; sometimes dioecious. 



4. C. STERILIS. Willd. 



Spike compound, ^ below, often dioecious ; spikelets 4^6, ovate, subap- 

 proximate ; perig. ovate, acuminate or subrostrate, bifid, compressed, triquetrous, 

 scabrous on the margin, equaling the ovate, acutish glume ; st. 2f high, erect 

 and stiff. Wet places, common. 



5. C. BROMolDEs. Schk. 



Spikelets numerous, alternate, $ below, sometimes all 9 5 perig. lanceo- 

 late, erect, acuminate, scabrous, nerved, bifid, twice longer than the ovate- 

 lanceolate glume. Common in small bogs, in wet places. 



6. C. SICCATA. Dewey. 



Spikelets numerous, $ above, often wholly J\ ovate, close or approximate ; 

 Jr. ovate, lanceolate, acuminate, compressed, nerved, bifid, scabrous on the 

 margin, equaling the ovate and lanceolate glume. Sandy plains, Westfield, 

 Mass., Davis; Ipswitch, Mass., Oakes; widely spread over the country, but not 

 abundant. 



7. C. SARTWELLII. Dewey. 



Spikelets 12 20, ovate, sessile, compact, bracteate, lower ones especially 

 fructiferous ; upper often J* ; perig. ovate, lanceolate, convexo-concave, subu- 

 late, short, 2-toothed, a little longer than the ovate and acute glume ; Ivs. flat, 

 linear, shorter than the stem. Junius, Seneca Co., N. Y., Sartwett. 



2. Stamens at the summit of 



a* Cephalvus, or fruit in heads. 



8. C. CEPHALOPHORA. Willd. 



Spikelets ovate, densely aggregated into an ovate head, bracteate, about 5 ; 

 perig. ovate, acuminate, compressed, bifid, scabrous on the margin, with a short, 

 ovate, and scabro-cuspidate glume which equals it ; st. 8 16' high. Borders 

 of fields and woods, common, but not abundant. 



9. C. VULPINOIDEA. Michx. (C. vulpinaeformis. Tuckermati. C. multi- 

 flora. Muhl.) Spikelets ovate-oblong, obtuse ; spike decompound, bracte- 

 ate, conglomerate; perig. ovate, acuminate, densely imbricate, bifid, tripli- 

 nerved, diverging, a little shorter than the ovate-cuspidate glume ; st. obtusely 

 triangular, round and leafy towards the base. Common in fields. 



0. microsperma. Dew. (C. microsperma. Wahl.} Spikelets closely aggregated, 

 whole spike less compact; perig. more convex, shorter, less acuminated into a 

 beak, very abundant. Grows with the other, in dry and moist situations. 



10. C. SETACEA. Dewey. 



Spikelets ovate, alternate, obtuse, conglomerate, bracteate; perig. ovate- 

 lanceolate, acuminate, compressed, bifid, some diverging, about equal to the 

 ovate-lanceolate, awned glume ; st. 2f high, acutely triangular, scabrous above 

 and striate. Wet places not abundant. 



11. C. MUHLENBERGII. Schk. 



Spikelets alternate, obtuse, approximate, with a long bract at the lower 



