C. paupercula of Michigan Flora.

In sphagnum bogs, coniferous swamps (tamarack, spruce, cedar), boggy hollows, and occasionally wet open ground; rock crevices along Lake Superior.

The terminal spike rarely has a few perigynia, but the plants can be distinguished from Carex atratiformis by their longer pistillate scales and pubescent roots. The leaves of C. magellanica tend to be flatter, broader and less glaucous than those of C. limosa, which has very slender, often ± involute glaucous blades. Also differs in the field from Carex limosa by growing in discrete clumps, lacking the long stolons of C. limosa.

The rare hybrid with Carex limosa, C. x connectens Holmb., has been collected once at the edge of a tamarack swamp in Delta Co.