Rocky Mountain Buttercup

The type specimen of Ranunculus macauleyi var. brandegeei L. D. Benson, from the Sangre de Cristo Mountains, Colorado, differs from typical R . macauleyi in its tall stem, broad, crenate-laciniate leaves, and sepals with pale or transparent hairs. These characteristics are suggestive of R . inamoenus , and the plant may be of hybrid ancestry.

Stems erect from short caudices, 6-15 cm, glabrous or sometimes pilose, each with 1-2 flowers. Roots slender, 0.7-1.3 mm thick. Basal leaves persistent, blades narrowly elliptic to lanceolate or oblanceolate, undivided, 1.5-4.5 × 0.5-1.1(-2.8) cm, base acute or long-attenuate, margins entire except for apex, apex truncate or rounded and 3(-5)-toothed. Flowers: pedicels glabrous or brown-pilose; receptacle glabrous; sepals 6-12 × 2.5-8 mm, abaxially densely brown-pilose; petals 5(-8), 10-19 × 6-17 mm; nectary scale glabrous. Heads of achenes ovoid or cylindric, 5-10 × 4-5.5 mm; achenes 1.5-1.7 × 1.2-1.3 mm, glabrous; beak slender, straight or recurved, 0.5-1.5(-2.2) mm.

Colo., N.Mex.

Flowering late spring-summer (Jun-Aug).

Sunny open soil of alpine meadows and slopes; 3300-3700m.