Plants densely cespitose; rhizome internodes 1.6-2.2 mm thick. Culms strongly purple-red to 3-7.4 cm high at base, 10-65 cm. Leaves: sheaths glabrous; blades green, widest blades 2.2-3.5(-3.9) mm wide, smooth abaxially. Inflorescences 0.31-0.94 of culm height; peduncles of lateral spikes barely scaberulous or smooth; peduncles of terminal spikes 1.8-28 mm, usually slightly exceeding lateral spikes; proximal bract sheaths tight, abaxially glabrous, sheath front convex, elongated 0.3-1.1(-1.7) mm beyond apex; ligules 0.4-2.2 mm; distal bract usually much exceeding terminal spike. Spikes 4-5, widely separate or distal 2-3 spikes overlapping; lateral spikes pistillate, with (1-)3-9(-11) perigynia, 4-19 × 5.1-8.2(-10.2) mm, ratio of spike length (in mm) to flower number = 1.4-1.9; terminal spikes (7-)10-29 × 1.1-2.1(-3.1) mm. Pistillate scales 2.8-5.4 × 1.7-2.5 mm, margins whitish, entire, apex with awn 0.8-2.6 mm. Staminate scales 3.6-5 × 1-1.8 mm. Anthers 2.9-3.7 mm. Perigynia distichously imbricate, 51-67-veined, inflated, unwrinkled, oblong-obovoid, orbicular or suborbicular in cross section, 3.6-4.4 × (1.8-)2-2.5(-2.8) mm, 1.6-2(-2.1) times as long as wide, dull, base very gradually tapered, apex abruptly contracted; beak straight, 0-0.2(-0.3) mm. Achenes obovoid, 2.6-3.3 × 1.6-2.1 mm, loosely enveloped by perigynia; stipe straight, 0.3-0.7 mm; beak straight, 0.05-0.3 mm.

Fruiting spring. Mesic deciduous forests, on flood plains and low on slopes just above flood plains, usually in calcium-rich loams and clay-loams; 30-300 m; Ark., La., Miss., Okla., Tenn., Tex.

Carex bulbostylis is common within much of its rather narrow range. It often occurs with C. amphibola and C. planispicata.