Agoseris heterophylla (Nutt.) Greene

Annuals. Stems 0 or 1 (erect, 0–5 cm). Leaves mostly erect, sometimes prostrate; petioles not purplish, margins glabrous or ciliate; blades usually oblanceolate to spatulate, rarely linear, 1–25 cm, margins entire or lobed; lobes 2–3 pairs, linear to spatulate, spreading to antrorse, lobules mostly 0, glabrous or densely hairy. Peduncles elongating after flowering, 3–60 cm in fruit, glabrous or glabrate, or basally puberulent and apically hairy to tomentose, sometimes stipitate-glandular. Involucres cylindric to hemispheric, 1–2 cm in fruit. Phyllaries in 2–3 series, green or medially rosy purple, sometimes purple-black spotted or tipped, subequal to unequal, margins glabrous or ciliate, faces usually puberulent to villous, mostly stipitate-glandular, sometimes glabrous; outer erect or spreading, adaxially usually villous to lanate, sometimes glabrous; inner erect, ± elongating after flowering. Receptacles epaleate. Florets 5–100(–300); corollas yellow, tubes 1–5 mm, ligules 2–15 × 1–3 mm; anthers 1–4 mm. Cypselae 7–16 mm, bodies mostly fusiform to obconic, sometimes tumid, 2–5(–10) mm, beaks 5–11 mm, lengths 1–4 times bodies, ribs 0 or alate, straight to strongly undulate, uniform or diminishing proximally; pappus bristles in 2–3 series, 4–9 mm.

Macrorhynchus heterophyllus Nuttall, Trans. Amer. Philos. Soc., n. s. 7: 430. 1841

Agoseris heterophylla is a liguliferous species in the family Asteraceae known by the common name annual agoseris or mountain dandelion. It is widespread in mostly drier regions of western North America from British Columbia to Baja California.