Plants rooted in muck; rhizomes relatively long. Stems commonly submerged except for terminal 10 cm or less. Leaves mostly 2-4 cm. Heads borne out of water. Corollas ca. 2 mm. Cypselae ca. 2 mm. 2n = 60.

Flowering (Dec-)Mar-May(-Aug). Water along streams, in slow-moving water (to 1 m deep) arising from calcareous outcrops; 50-3000 m; Tex.; Mexico (Coahuila, Nuevo León).

Shinnersia rivularis has been treated within Trichocoronis. The genera differ in features noted in the couplet below. Sclerolepis, of the southeastern United States, apparently also is closely related, and its recognition as separate reinforces recognition of Shinnersia.