52 Mackenzie — A New Carex from Alberta. 



gynaecandrous and clavate at base; lowest bract leaflet-like, slightly 

 sheathing, not purplish tinged, shorter than or exceeding the inflores- 

 cence, the others much reduced ; scales broadly ovate, obtuse or slightly 

 acute, black, the niidvein obsolete, the upper margins not at all or but 

 very slightly hyaline, about the width of but markedly shorter than the 

 perigynia; perigynia olive-green, slightly purplish-spotted, membrana- 

 ceous, slightly inflated and subtriangular, nerveless, puncticulate, nar- 

 rowly obovoid, 3.25 mm. long, 1.75 mm. wide, glabrous, round-tapering 

 at base, minutely roughened on margins above, abruptly contracted into 

 a minute, shallowly bidentate, purplish-black beak, scarcely 0.5 mm. 

 long; achenes triangular, obovoid, 1.5 mm. long, 0.75 mm. wide, scarcely 

 stipitate, half the length of the perigynia; style little exserted, its base 

 slender; stigmas three, very short. 



The type, collected at the head of Smoky River, Alberta, August 5, 

 1911, by X. Hollister (No. 14), is in the U. S. National Herbarium, No. 

 (522, 051. J. H. Riley's No. 61, from South Fork of Moose River, British 

 Columbia, July, 1911, is also to be referred here ( U. S. National Herba- 

 rium, No. 622,594 ). 



Carer atrata L. and several of its close allies, to which the present species 

 is related, are all distinguished by the strongly compressed perigynia, and 

 in all of them the achene is much narrower than the perigynium, the 

 empty part of the latter appearing almost wing-like. The slightly inflated 

 subtriangular perigynium of the present species, which is but little wider 

 than the achene, is in strong contrast to the perigynium of any of these 

 species. 



