Most characteristically a plant of sphagnum bogs and fen mats where the well developed rhizome system makes it one of the major components of floating mats; remaining as a relic under black spruce, tamarack, and cedar. Usually in even wetter sites than Carex pellita, and only rarely growing with it.

Late in the season, the fine tips of the leaves of vegetative shoots especially, dry, curl, and become a  glossy whitish or straw colored, lending a distinctive look to large colonies that is visible from a great distance, even from the air. 

Very rarely, individuals will have sparse, fine pubescence on the sheaths; these are not accommodated in the keys.