Hemizonia filipes Hooker & Arnott, Bot. Beechey Voy. 356. 1838.

Leaf blades (proximal) 3–10 cm × 2–8 mm. Phyllaries 3–5 mm. Disc corollas 3–4.5 mm. Cypselae 2.5–3.5 mm. 2n = 28.

Flowering Jun–Oct. Banks and dry beds of streams and pools, often in rocky sites or alkaline clays; 30–600 m; Calif.

Holozonia filipes is the only perennial, continental tarweed with white corollas or filiform peduncles and is unique among the perennials for occurring in low-elevation, summer-hot, interior habitats. Like most of the perennial, continental tarweeds, H. filipes is self-incompatible and has a geographic distribution marked by major disjunctions between some populations.