Carex heliophila Mackenzie, Torreya 13: 15. 1913; C. pensylvanica Lamarck var. digyna Boeckeler; C. pensylvanica subsp. heliophila (Mackenzie) W. A. Weber

Staminate spike peduncles 1.2–4.5 mm. Proximal cauline pistillate spikes sessile, globose to ovoid. 2n = 36, 40.

Fruiting mid Apr–early Jul. Open, well-drained sandy, loamy, and loess soils in prairies (grazed and ungrazed) and ponderosa pine woodlands; 100–1500 m; Alta., B.C., Man., Ont., Sask.; Colo., Ill., Ind., Iowa, Kans., Mich., Minn., Mo., Mont., Nebr., N.Mex., N.Dak., S.Dak., Wis., Wyo.