Coefficient of Conservatism:
Coefficient of Wetness:
A. A. Reznicek
Cedar and cedar-fir forests and borders, wet meadows, rich moist deciduous or mixed forests, jack pine plains, rock pools along Lake Superior. A calciphile especially characteristic of margins of mixed coniferous forests on thin soil over limestone, and here often found with C. capillaris, which it resembles in general habit (although larger and pubescent).
Carex ×knieskernii Dewey is the hybrid with C. arctata, and occurs sparingly where the parents come into contact. It is sterile and more or less intermediate in morphology, with spikes longer and narrower than C. castanea, almost as narrow as in C. arctata, and hairy foliage. The rarer hybrid C. castanea × C. gracillima resembles C. ×knieskernii closely, but has shorter beaks.