366. North American Ci/jjeracetr. 
Hab. Rocky mountains, and barren grounds between 
lat. 64° and the Arctic sea, Dr. Richardson ! 
Obs. I can perceive no essentia] difference between Eu- 
ropean specimens of E. sjncafa and those from the Rocky- 
Mountains, from which Prof, Dewey drew his description of 
Kohresia Jilijhrmis, except that in very mature specimens of 
the American plant the spike is somewhat more loosely 
flowered. The name under which the plant is described in 
Sillinian's Journal is credited to Dr. Torrey by some mistake. 
Tribe VIIL CARICEiE. 
Flowers diclinous. Scales of the spikes imbricated on 
all sides. Nut wholly enclosed in an urceolate or bottle- 
shaped perig) nium.* 
CAREX, Linn. 
Spikes one or several, androgynous or unisexual, rarely 
dioecious. Stam. Fl. Stamens -3. Pist. Fl. Perigy- 
NiUM bidentate, emarginate or truncate at the apex. Style 
2 or 3-cleft. Nut lenticular, plano-convex, or triangular, 
crowned with the lower portion of the persistent and continuous, 
or rarely articulated, style. — Culms triangular, leafy through- 
out, or only at the base ; spikes terminal or axillary, distant or 
approximate, or variously aggregated. 
Carex, Linn. gen. pi. no. 1946; Juss. gen. p. 36 ; Lain'Tc. 
ill. X. 752 ; Schkuhr, car. 1. p. 1. et tab. mult. ; R. Brown, 
* The urceolate perigynium of Carex, Uncinia, &c. is considered as 
resulting from the union of two scales, like those which enclose the 
flowers of Elyna and Kohresia, and not as analogous to the setiform peri- 
gynium of Scirpeas and Rhynchosporesc. In the former case it repre- 
sents bracts of the second order ; in the latter it may he viewed as a 
rudimentary perianth. 
