Fruit surrounded by a perigynium. Range in the Canadian Arctic Archipelago wide-spread. Ecology and habitat. Occurs in a variety of moist habitats, particularly sedge meadows. It has been noted both around the margins of wet meadows and in the deeper, more saturated areas.
Typical associates are Carex aquatilis var.
It has also been reported in substrates of widely ranging organic content, including bare wet sand, humic seepage slopes and fairly developed peaty areas. It is noticeably absent from Greenland and occurs in Eurasia only in the Chukot Peninsula and Koryakskiy Mountain region of extreme eastern Russia. It is one of the few truly northern species of sedge, being widespread in the Arctic Archipelago and south as far as northern British Columbia, the southern boundary of the Northwest Territories and northern Quebec. Carex membranacea frequently occurs as a dominant in a wide variety of open, moist habitats that often have a well-developed peat layer. It does not appear to grow in standing water or in shoreline communities.