Annuals or biennials, 30-70 cm. Phyllaries 8(-12), mostly linear to narrowly oblanceolate. Rays 0. Disc florets 10-20; corollas creamy to bright yellow, mostly 4-4.5 mm, lobe lengths 0.3-1 times throats; anthers yellowish. Cypselae 2.5-4+ mm; pappus scales 3-5 mm. 2n = 24. Flowering summer-fall. Open, often disturbed, places; 900-2100 m; Ariz., Calif., Nev. Occurrences of Hymenothrix loomisii in California have been geographically scattered, sporadic, and nonpersistent introductions.

Plant: Annual, biennial, or short-lived perennial herb, < or = 1.5 m; stems 1-several from base, erect Leaves: basal and cauline, alternate; lower petioled, dissected into 1-2 mm wide linear lobes, glabrous or short-hairy; upper reduced, sessile INFLORESCENCE: primary inflorescence a head, each resembling a flower; heads radiate or discoid, in many-headed, ± flat-topped clusters; peduncles 1-7 cm, bracts 0 or scattered, linear; involucre obconic; phyllaries 3-5 mm, linear, obtuse to acute, tips often cream, glabrous to gland-dotted or puberulent Flowers: corollas 5-7 mm, cream, outer often larger than inner, ± bilateral; anthers 2-3 mm, yellow to light brown Fruit: 3-5 mm, club-shaped, 4-5-angled, ± hairy; pappus scales 3-7 mm, bristle-tipped Misc: Disturbed sites; < 1000 m.