Carex albonigra growing in rivulets on the talus at Sundance Pass, between Lake Fork and West Fork of Rock Creek, Beartooth Mountains, Carbon County, Montana. The beaks of the perigynia are less than 0.5 mm long. Those of the similar Carex nelsonii and Carex pelocarpa are over 0.5 mm long.
Zone B, near water, side of hill, Partial shade,uncommon
Zone B, Uncommon, Partial shade, near river bank
Zone B, Uncommon, Shaded, near riverbank