Annuals, green, to 20(-30) cm, glabrous or puberulent. Stems erect (branched from bases). Leaves alternate; blades 15-40 mm overall, lobed, lobes 5-13, linear. Peduncles 10-70 mm, glabrous or puberulent. Calyculi 0, or of 1-2 subulate bractlets, lengths less than ¹/2 phyllaries. Involucres obconic to campanulate, 5-6 mm. Phyllaries 12-15, margins of outer distinct almost to bases, abaxial faces glabrous or puberulent. Ray florets 8-12; corollas bright yellow, laminae 4-6 × 2-3 mm. Disc florets 30-45; corollas yellow, 3 mm. Cypselae 3 mm; pappi either of erose scales 0.3-0.6 mm, or of 3-5-aristate scales 2-3 mm. The two varieties of Thymophylla aurea are sometimes found in mixed populations, which may include intermediate plants.