Ranunculus austro-oreganus

Ranunculus austro-oreganus is doubtfully distinct from R . occidentalis var. howellii . L. D. Benson (1954) described the stem as bulbous-based and similar to that of R . bulbosus , but a differentiated base is not evident in material I have seen (some of which was cited by Benson).

Stems erect or ascending, never rooting nodally, crisped-pilose, base not bulbous. Roots never tuberous. Basal leaf blades broadly rhombic to semicircular in outline, 3-parted, 2.8-4.3 × 3-5.5 cm, segments 3-lobed, ultimate segments lanceolate, margins entire or toothed, apex narrowly acute or acuminate. Flowers: receptacle glabrous; sepals reflexed 1 mm above base, 4-6 × 1.5-3 mm, densely pilose; petals 5, abaxially red, adaxially yellow, 10-12 × 4-6 mm. Heads of achenes hemispheric, 4-7 × 7-10 mm; achenes 3.4-4.2 × 2.8-3.2 mm, sometimes basally pilose, margin forming narrow rib 0.1-0.2 mm wide; beak persistent, lance-subulate, straight or somewhat curved distally, 1.6-2.6 mm.

Oreg.

Flowering spring (May).

Grassy hillsides; of conservation concern; 500m.

Ranunculus austro-oreganus, the Southern Oregon buttercup, is a plant species endemic to the region around Medford, Oregon. It grows on grassy areas at elevations less than 500 m (1650 feet).

Ranunculus austro-oreganus is an erect to ascending herb not rooting at the nodes. Leaves are 3-parted, up to 5 cm (2 inches) long and about as wide. Flower petals are each up to 12 mm (0.5 inches) long, yellow with prominent red veins visible on the back but not on the front. Achenes are hemispheric with a persistent straight or curved beak. The species is closely related to R. occidentalis.