Intermountain horkelia

Horkelia pseudocapitata Rydberg ex Howell, Fl. N.W. Amer., 180. 1898; H. fusca subsp. pseudocapitata (Rydberg ex Howell) D. D. Keck; Potentilla douglasii Greene var. pseudocapitata (Rydberg ex Howell) Jepson

Stems 3–6 dm. Basal leaves green, 10–35(–40) cm; leaflets 4–6(or 7) per side, narrowly to broadly obovate, 10–30(–35) × (5–)10–20(–25) mm, 1/2 to nearly as wide as long, divided 1/5–1/4 to midrib into 8–14 teeth, surfaces not obscured, ± sparsely hirsute to glabrate. Cauline leaves 1–4(or 5); leaflets of proximalmost 2 or 3(–5) per side. Inflorescences green to reddish purple, congested to open, comprising 1/6–1/3 of stem, composed of 10–30-flowered glomerules, glandular hairs not or obscurely red-septate; bracts acute-lobed, not obscuring pedicels and flowers at maturity. Flowers: epicalyx bractlets 2–3.5(–4) mm; hypanthium 2 × 2.5–4 mm; petals (3–)4–6 mm; filaments 0.5–1.5 mm, usually longer than wide, anthers 0.5–0.6 mm; styles 1–1.5 mm. Achenes 1.6–1.8 mm. 2n = 28.

Flowering summer. Dry meadow edges, often with sagebrush, aspen, and/or willows, open conifer woodlands, mainly on volcanic or granitic soil; 900–2300 m; Calif., Idaho, Nev., Oreg.

The application of the epithet pseudocapitata here differs significantly from that of P. A. Rydberg (1908c), D. D. Keck (1938), and most floras, who used it for the taxon that is here called var. brownii. Instead, var. pseudocapitata encompasses the bulk of what had been called var. (or subsp.) capitata, except in mountains bordering the Palouse Prairie in Idaho, Oregon, and Washington. For nomenclatural details, see B. Ertter and J. L Reveal (2007).

As here circumscribed, var. pseudocapitata is a relatively large, big-petaled variety that grows in the mountains in and bordering the northern Intermountain Region in northeastern California (primarily the Warner Mountains), northern Nevada, southeastern Oregon, and southern Idaho, extending northward along valleys from Camas to Blaine counties. Intermediate plants are common where the range intersects those of var. brownii, var. capitata, and var. parviflora, though in the core of its range var. pseudocapitata is reasonably distinctive and uniform.