Plants cespitose. Culms straight, 10-50 cm, tallest ones 25-50 cm. Leaves of flowering stems usually shorter than culms, 5-20 cm × 1.5-2.9 mm; ligules on distal cauline leaves truncate or rounded. Inflorescences: peduncles of terminal staminate spikes 0.5-8 mm, 0.2-0.5 length of staminate spikes; bracts to 20 cm × 1.1-2.9 mm, 1.5-4 times as long as inflorescences; inner band of sheaths concave or truncate. Spikes: proximal pistillate spikes (1-)2-5, approximate, subsessile or short-pedunculate, globose to elliptic, 8.5-19.9 × 4.1-9.8 mm; terminal staminate spikes pedunculate, 12-21 × 1.3-2.7 mm. Scales: pistillate scales yellowish green, inconspicuous among perigynia, 1.7-2.6 × 0.8-1.2 mm; staminate scales yellowish green, ovate, 2.9-4.4 × 0.8-1.6 mm, apex obtuse or acute to acuminate. Anthers 1.1-2.9 mm. Perigynia reflexed, yellowish green, 3.5-4.8 × 1.1-1.7 mm, apex gradually narrowed; beak 1.4-2.5 mm, forming an angle of 13-48° with body, smooth. Achenes 1.2-1.5 × 1-1.2 mm. 2n = 64. Fruiting Jun-Aug. Acidic, sandy or organic substrates on open, emergent shorelines, not found on lime-rich soils; 0-500 m; N.B., Nfld. and Labr., N.S., Ont., Que.; Conn., Ind., Maine, Mass., Mich., Minn., N.H., N.J., N.Y., Ohio, R.I., Vt., Wis. The name Carex flava var. fertilis Peck has been misapplied to C. cryptolepis.
From Flora of Indiana (1940) by Charles C. Deam
Frequent in northern Indiana on marly lake borders and in marshes rich in marl; infrequent on wet sandy lake shores.
Much like no. 154 [Carex flava L.]; stems 2-6 dm, surpassing the lvs, these 1.5-3.5 mm wide; pistillate scales lance-ovate, about equaling the perigynium-body, about the same color as the perigynium and thus inconspicuous; perigynia greenish to yellowish or golden-brown, 3.2-4.8 mm, abruptly contracted to the smooth beak 1.2-1.5 mm. Wet meadows and shores in calcareous districts; Nf. to Minn., s. to N.J., O., and Ind. (C. flava var. fertilis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.