Stems erect, sparsely pilose. Basal leaf blades reniform to semicircular, undivided or shallowly 3-lobed, 2.5-5 × 3-7 cm, base truncate to nearly cordate, margins crenate or dentate, apex rounded or obtuse. Flowers pedicellate; receptacle hispid; sepals 5, reflexed 1 mm from base, 3-5 × 1-2 mm, hispid; petals 5, 4-5 × 2-3.5 mm. Heads of achenes hemispheric to globose, 4 × 6 mm; achenes 15-20 per head, 2.5-3 × 2-2.5 mm, faces covered with high sharp tubercles or low spines, glabrous, margin smooth; beak deltate, straight, 0.8-1 mm. Flowering spring (Mar-May). Roadsides; 0-100 m; introduced; Ala., La., Tex.; native to Europe. A form of Ranunculus marginatus , with the fruits weakly tuberculate or almost smooth, similar to the smooth-fruited forms of R . sardous , is found in Europe; it is not known from North America.