24 Holm, The genus Carex in North -West America. 



Ca r i ces x>hii s o c a r p a e. 



Of these C. pluisoclüaena from Yukon and C. amhusta from 

 Alaska are actually the only northwestern types of this grex, 

 which is otherwise so very highly developed in this region. Never- 

 theless we have, no doubt, a most important center of distribution 

 in Alaska and Yukon where these species are accompanied by 

 the very characteristic C. ])]u)socarpa , rotundata, utriculata, pulla 

 and compada, an assemblage of species of striking and very 

 Singular aspect. C. pluisocarpa extends to Alberta, Montana and 

 Wyoming, but is nowhere so abundant as on the Alaskan coast 

 and adjacent islands, from where it evidently originated. 



Carices physocephalae. 



C. Breweri is a western type and confined to the Pacific coast: 

 Washington, Oregon and California, but is only known from a few 

 stations, and belongs more properly to the Californian Flora. 



Ca r i ces rliy n c h op h o r a e. 



The eastern species C. monile occurs here with the variety 

 pjacifica, which may be considered as a type of this region, while 

 the var. colorafa is distributed throughout Montana, Wyoming and 

 Colorado. 



The number of types characteristic of North-West America 

 aggregates 50 species including a very few varieties, and we have 

 recorded in all 195 species and varieties. The region which we have 

 treated extends from the 42^ to the 70^ northern latitude, and 

 from the 114^ to the 170^ western longitude. 



Let US now examine and compare the Carices that occur on 

 the Atlantic coast between the 42^ n. 1. (Cape Cod) and the 

 70^ (Baffins' Land and west-coast of Greenland). From this 

 region 180 species are known besides about 70 varieties; however 

 only 13 of these species appear to be characteristic of North-East 

 America, and 6 of these are Greenland types. When compared, 

 these figures show the prevalence of types on the Pacific coast, 

 which becomes still more conspicuous, if we include CaUfornia. 

 The number of species so far known from this State is about 90, 

 25 of which are peculiar to the State, thus the Pacific coast 

 possesses altogether 75 types. Among these Californian species 

 are several which are remarkably distinct from the northern, and we 

 might mention for instance: C. vitrea, chrpsolepis, senta, serratodens, 

 lacunariim, Mendocinensis, gynodyyiama, luzulma, aequa etc. 



This number of Californian types is relatively large, when we 

 remember that only a very few species are characteristic of the 

 Southern Atlantic States, from Virginia to Florida incl. : C. EUlottU, 

 juncea, turgeseens, Carol'miana, BaltzeUi, Chapmani, dasycarpa and 

 Fraseri. 



We might, furthermore, compare the greges as represented on 

 both coasts, and from this will be seen that the Leucocephalae 

 (C. Fraseri) are confined to the Atlantic, the Physocephalae (C. 

 Breiveri) to the Pacific. While certain greges are equally well 

 represented on both coasts, thcre are others which show a less 

 uniform distribution, for instance: Pterocarpae. Cenchrocarpae, 

 Lpjoclüaenae, Microcarpae. HymenocMaenae and Bliynchophorae,. 



