Porter’s groundsel

Senecio porteri Greene, Pittonia 3: 186. 1897, based on S. renifolius Porter, Syn. Fl. Colorado, 83. 1874, not Schultz-Bipontinus 1845; S. aureus Linnaeus var. alpinus A. Gray

Perennials, 3–10+ cm; rhizomatous (rhizomes branched). Stems 1 (often cyanic), glabrous. Basal leaves (relatively turgid, abaxial faces cyanic) petiolate; blades reniform to subreniform, 5–15+ × 5–25+ mm, bases abruptly contracted to cordate, margins usually crenate, sometimes wavy. Cauline leaves abruptly reduced (1–4, sessile; bractlike, entire). Heads borne singly. Peduncles ebracteate, glabrous. Calyculi conspicuous (bractlets often cyanic). Phyllaries 13 or 21, deep red, 8–10+ mm, glabrous. Ray florets 8 or 13; corolla laminae 8–10+ mm. Disc florets 40–50+; corolla tubes 2.5–3.5 mm, limbs 2.5–3.5 mm. Cypselae 1.5–2.5 mm, glabrous; pappi 4–5.5 mm.

Flowering mid Jul–mid Aug. Steep talus slopes in alpine habitats; 2800–3900 m; Colo., Oreg., Wash.

Multiple collections of Packera porteri are known from Colorado; single collections are known from Oregon (1899; collector indicated few plants were seen) and Washington (1996).