Hemizonia minima A. Gray, Proc. Amer. Acad. Arts 6: 548. 1865; Madia minima (A. Gray) D. D. Keck

Leaf blades 5–25 × (0.5–)1–3 mm. Involucres (1–)2–4 × (1–)2–4 mm. Disc corollas 1–2.5 mm. Ray cypselae 1.8–2.8 mm; disc cypselae 1.8–2.8 mm. 2n = 42–44.

Flowering Apr–Aug. Gravelly or rocky, usually open sites, scrublands, meadows, forests; 300–2900 m; B.C.; Calif., Idaho, Mont., Nev., Oreg., Wash.

Hemizonella minima is self-compatible, like most other tarweeds that are distributed widely in western North America. Taylor 8147 (JEPS), from the Sierra Nevada (Tioga Peak, Mono County, California), is an unusually late-flowering (15 Sep 1982) and high-elevation (2900 m) collection.