Subshrubs or shrubs, ashy white, 10-30 cm, lanate to tomentose. Stems erect. Leaves all or mostly alternate; blades not lobed, linear to filiform, 10-15 × 0.3-1 mm, margins usually entire, sometimes 3-fid distally. Peduncles 10-30 mm, tomentose. Calyculi of 3-4 linear bractlets, lengths ¹/2+ phyllaries. Involucres campanulate, 5-7 mm. Phyllaries 12-13, margins of outer distinct less than ¹/4 their lengths, abaxial faces tomentose. Ray florets 12-13; corollas golden yellow, laminae 6-8 × 3-4 mm. Disc florets ca. 30; corollas yellow, 4.5-5 mm. Cypselae 3-4 mm; pappi of 10-11 subequal scales 4-5 mm (each 3-5-aristate). 2n = 16.

Flowering early spring and late summer, following rains. Light, sandy soils; of conservation concern; 50-100 m; Tex.

Thymophylla tephroleuca probably grows also in adjacent Mexico. It is in the Center for Plant Conservation´s National Collection of Endangered Plants.