Annuals, perennials, subshrubs, or shrubs, (1-)5-30 cm. Stems erect to spreading or decumbent, branched from bases or ± throughout. Leaves cauline; opposite or alternate; petiolate or sessile; blades often pinnately lobed, blades or lobes spatulate to linear or filiform, ultimate margins entire or toothed, faces glabrous or arachnose, canescent, floccose, lanate, puberulent, or tomentose (bases little, if at all, bristly-ciliate, oil-glands scattered in laminae or submarginal). Heads usually radiate, sometimes discoid or radiant, borne singly. Calyculi 0 or of 1-8 deltate to linear bractlets (bearing oil-glands). Involucres campanulate to obconic, 2-7 mm diam. Phyllaries persistent, 8-13(-22) in ± 2 series (strongly connate 2/3-7/8+ their lengths, seldom with outer margins distinct more than 1/2 their lengths, exceptions: T. aurea, T. pentachaeta var. belenidium), usually bearing oil-glands. Receptacles convex, smooth or ± pitted, epaleate. Ray florets usually 5, 8, 13, or 21, pistillate, fertile; corollas usually yellow to orange, rarely white. Disc florets 16-100+, bisexual, fertile; corollas yellow to orange, tubes shorter than ± cylindric throats, lobes 5, deltate. Cypselae obpyramidal, obconic, or cylindro-clavate, glabrous or sparsely strigillose; pappi persistent, coroniform or of 10(-20) distinct scales (each scale erose, or 1-5-aristate, or a fascicle of 5-9 basally connate bristles). x = 8.
This project was made possible in part by the Institute of Museum and Library Services [MG-70-19-0057-19].