Holm, The genus Carex in North-West America. 
19 
World homologues may be sought among C. tricostata, tiirfosa and 
limula. 
In passing to C. rigida^ the typical plant has been collected at 
Port Clarence, on St. Paul Island and in Yukon, while the var. 
infercdpina seems to be more frequent and has been collected 
at .several stations in Alaska and Washington. 
In regard to the occurrence of C. aquatilis in our region, the 
type seems to be rare in Alaska and Yukon, while the var. 
epigejos is quite frequent (Port Clarence, Point Barrow, Popoff 
islands etc.). In C. sphacelcda and chionophila Yukon possesses 
two types, which approach C. aquatilis, yet the color of the spikes 
and the structure of the perigynium is somewhat different, hence 
we prefer to consider them distinct from this, at least at present. 
The stoloniferous and very leafy C. consimilis is another species 
characteristic of Yukon, which according to habit also reminds of 
C. rigida and hgperhorea, and the writer feels indeed uncertain 
as to where it may be properly placed in the grex, especially on 
account of the orbicular, purplish-spotted perigynium with the 
prominently denticulate margins and ver}^ short, entire beak, 
characters that seldom go together among these species. 
A near ally is C. cgclocarpa, also from Yukon, of which the 
perigynium is turgid, nearly globose, brownish with purplish spots 
above, but glabrous. C. interrupta, a rare species, so far only 
known from river-beds, river-banks and bottom-lands in Oregon 
and Washington, is another type, readily distinguished from all 
the others by the very long and slender pistillate spikes, and by 
the perigynia which are two-nerved, sparingly denticulate, with 
the short, obliquely cut beak. 
It is now interesting to see that to these members of the 
2Iicrorhifnchae may be added C. acutina, which has been found 
at some stations in Yukon, Idaho and Oregon, but which is much 
more frequent in the mountains of Wyoming, Montana and Colo¬ 
rado and to where it more properly belongs. Like C. vulgaris 
and aquatilis this species represents really a central type of a 
group of species, not so very unlike the European acuta^) and 
its allies. As a matter of fact C. limnocharis from Yukon resem- 
bles very much C. p)rolixa and seems allied to C. acutina to the 
same extent as pu'olixa to acuta. C. variahilis, which shows much 
the same distribution as acutina, has also been observed in our 
region, but is evidently rare. 
A species that appears intermediate between C. variahilis 
and lenticularis is C. pacligstoma from Oregon and Washington, 
the perigynium of which shows a peculiar thick beak with the 
orifice narrow and slightly emarginate on the outer face. To this 
same group belongs C. Sitchensis, which for many years has been 
q The Statement by Mr. Ostenfeld in Flora Arctica (p. 73) that C. 
acuta occurs in ,,Northern North America“ is uncorrect, since it has, so far, 
never been observed on this continent. This same writer has, furthermore, 
credited C. caespitosa L. and C. stricta Good. to North America, where they 
have^ never been found. The geographical distribution as given in Flora 
Arctica is altogether very faulty in regard to many of the species treated, 
and we regret to say that the synonyms and diagnoses fare no better. 
2 * 
