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The genus Carex in North-West America. 
By 
Theo. Holm, 
Brookland D. C. 
The present enumeration of Carices is based upon some very 
extensive collections from Alaska, Yukon, British Columbia, Wa¬ 
shington, Idaho and Oregon, made by Alessrs. Wm. C. Cusick, 
Walter H. Evans, L. F. Henderson, C. V. Piper and Wm. 
N. Suksdorf; the writer has, also, had access to the herbaria of 
the Canadian Geological Survey and of the U. S. National IMuseum. 
For the liberal loan of these collections and for the numerous 
specimens, that have been kindly donated to the writer, we wish 
to express our sincerest gratitude. 
As stated in a previously published paper, it is our intention 
to discuss the geographical distribution of these species within 
the area given, and throughout the northern hemisphere: the 
arctic regions and the mountaineous districts farther South. While 
thus offering these data in regard to the geographical distribution, 
we have thought that the enumeration might be of some interest 
to students of plantgeography, as a record of all the species that 
have been found growing within this area, from which will be seen 
the predominance of certain ,,greges“, the total absence of others, 
and finally the association of allied types with apparently local 
and somewhat isolated species. 
By giving an account of the association of such isolated types, 
we hope that the establishment of these may be better understood 
than by the diagnoses alone. For instance in regard to several 
of the species, which have been described as new (1. c.), it appears 
as if their association with more or less related species to some 
extent justifies our views in considering them as distinct, at least 
so long as no Intermediate forms are known to be in existence. 
b The author: Studies in the Cyperaceae (Am. journ. of sc. Vol. XX. 
1905. p. 301). 
Beihefte Bot. Centralbl. Bd. XXIL Abt. II. Heft 1. 
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