Chromolaena bigelovii

Shrubs, 50-150 cm. Stems erect, sparsely puberulent. Petioles 1-4 mm. Leaf blades deltate to deltate-lanceolate or ovate-lanceolate, 3-7 × 1-4 cm, margins serrate to dentate (abaxial faces reticulate-veiny with raised whitish, secondary veins, minutely gland-dotted). Heads usually in 3s, sometimes borne singly. Peduncles 0 or 2-8(-12) mm. Involucres turbinate to campanulate, 5-7 mm. Phyllaries in 4-5 series, apices of the inner appressed, acute (not petaloid or expanded). Corollas pale blue or white.

Flowering Oct-Dec. Dry limestone hills in oak woodlands, talus; 1000-1800 m; Tex.; Mexico (Coahuila, Nuevo León, San Luis Potosí).