Cordilleran drymocallis or wood beauty

Potentilla convallaria Rydberg, Bull. Torrey Bot. Club 24: 249, plate 306. 1897; Drymocallis arguta (Pursh) Rydberg subsp. convallaria (Rydberg) Soják; P. arguta Pursh subsp. convallaria (Rydberg) D. D. Keck; P. arguta var. convallaria (Rydberg) Th. Wolf

Caudex branches short. Stems usually solitary, sometimes tufted, 4–9(–10) dm; base 2–5 mm diam., ± densely septate-glandular. Leaves sparsely to moderately, rarely densely, hairy; basal (10–)15–25(–30) cm, leaflet pairs (2–)3–4; terminal leaflet usually obovate, sometimes elliptic, 3–5(–6) × 1.5–4.5 cm, teeth double, 9–16 per side, apex rounded-obtuse; cauline (1–)2–4, well developed at least proximally, leaflet pairs usually 3. Inflorescences (5–)10–40-flowered, not leafy, congested to open, (1/8–)1/6–1/3(–1/2) of stem, narrow, branch angles 5–20°. Pedicels 1–5 (proximal to 25) mm, sparsely to ± densely short-hairy, predominantly septate-glandular. Flowers opening ± widely; epicalyx bractlets narrowly elliptic, (2–)4–6 × 0.7–1.5 mm; sepals ± spreading, (4–)5–8(–10) mm, apex acute; petals not or scarcely overlapping, ± spreading, cream-white to pale yellow, obovate-elliptic, sometimes broadly so, (3–)5–8 × (2–)4–6 mm, ± equal to sepals; filaments 1.5–2.5 mm, anthers 0.7–1 mm; styles thickened, 0.8 mm. Achenes light brown, 1 mm.

Flowering (May–)Jun–Aug. Dry to seasonally moist meadows, open forests, sagebrush and grassy rocky slopes; 100–3000 m; Alta., B.C., Yukon; Alaska, Ariz., Colo., Idaho, Mont., Nev., Oreg., Utah, Wash., Wyo.

Drymocallis convallaria is widespread in western North America, occurring mostly west of the Continental Divide from south-central Alaska to Arizona. It differs from most sympatric species in usually having a single thick stem, a narrow inflorescence, and cream-white to pale yellow petals, at most only slightly longer than the sepals.

Some collections from southern Idaho and northern Nevada that have very small petals in the size range of Drymocallis micropetala are included here on the basis of glandular pedicels. Excluded here are comparably small-petaled plants from the Warner Mountains of California and Oregon that have the aspect of D. convallaria but the blunter, redder achenes of D. glandulosa. Populations in northern Idaho and adjacent Washington that approach D. arguta in size and vestiture are provisionally treated as D. convallaria on the basis of leaflet shape. Specimens from New Mexico previously assigned to this taxon have largely been redetermined to D. arguta in the strict sense. See also discussions of Potentilla fissa var. major under 1. D. fissa, and of D. valida under the genus discussion. The illegitimate names P. glutinosa Nuttall ex Rydberg and D. glutinosa Rydberg have been applied most often to D. convallaria.