Inflorescences 10--30 cm; heads 20--30-flowered. Capsules exserted, valves separating at dehiscence. 2n = 40.

Fruiting late spring--fall. Moist to wet open sites, usually sandy, sometimes peaty, exposed or marshy shores of ponds, lakes, and streams, ditches, and fields; 0--100 m; Ala., Ark., Fla., Ga., Kans., La., Miss., Mo., N.C., Okla., S.C., Tenn., Tex., Va.

Juncus validus var. validus closely resembles J. polycephalus but differs in having complete septa, long-exserted capsules, and terete stems.