White Mountains horkelia

Potentilla hispidula (Rydberg) Jepson

Plants 0.7–3 dm diam. Stems ascending to erect, 1–2.5 dm. Basal leaves 3–10 × 0.4–0.8 cm; leaflets (6–)10–14 per side, ± overlapping at least distally, cuneate to flabellate, 2.5–4(–6) mm, divided 3/4+ to midrib into 3–6 oblanceolate to obovate lobes, hispid. Cauline leaves 3–7. Pedicels 2–8(–12) mm. Flowers 3–15, 10 mm diam.; epicalyx bractlets linear to lanceolate, 1.5–3 × 0.2–0.5 mm, ± 2/3 length of sepals; hypanthium 1.8–3 × 3–4 mm, ± 1/2 as deep as wide, interior sparsely pilose; sepals reflexed, broadly lanceolate, 2.5–4(–5) mm, hairs stiff, 0.5 mm; petals not pink-tinged, oblanceolate to oblong or narrowly elliptic, 2.5–5 mm, apex rounded to truncate, sometimes slightly emarginate or mucronate; filaments white, 0.5–2 × 0.4–0.6 mm, glabrous or sparsely pilose adaxially, anthers 0.5–0.9 mm; carpels (10–)12–18(–20); styles 1.8–2.2 mm. Achenes brown to dark brown, 1.5–2 mm.

Flowering summer. Dry, rocky alpine flats, in subalpine conifer woodlands; of conservation concern; 3000–3400 m; Calif., Nev.

When describing Horkelia hispidula, Rydberg associated it with H. sericata in his group Sericatae. The species is known only from the White Mountains of California and adjacent Nevada.