Cursed Buttercup

Ranunculus sceleratus varieties were used by the Thompson Indians as a poison for their arrow points (D. E. Moerman 1986).

Stems erect, glabrous, rooting at base, only very rarely rooting at proximal nodes. Leaves basal and cauline, basal and proximal cauline leaf blades reniform to semicircular in outline, 3-lobed or -parted, 1-5 × 1.6-6.8 cm, base truncate to cordate, segments usually again lobed or parted, sometimes undivided, margins crenate or crenate-lobulate, apex rounded or occasionally obtuse. Flowers: receptacle pubescent or glabrous; sepals 3-5, reflexed from or near base, 2-5 × 1-3 mm, glabrous or sparsely hirsute; petals 3-5, 2-5 × 1-3 mm; nectary on petal surface, scale poorly developed and forming crescent-shaped or circular ridge surrounding but not covering nectary; style absent. Heads of achenes ellipsoid or cylindric heads, 5-13 × 3-7 mm; achenes 1-1.2 × 0.8-1 mm, glabrous; beak deltate, usually straight, 0.1 mm.

Herbs annual. Roots fibrous, subequally thick. Stems 10--75 cm, glabrous or sparsely puberulent, branched above. Basal leaves 5--13; petiole 1.2--15 cm, subglabrous or sparsely pubescent; blade 3-partite, pentagonal, reniform, or broadly ovate, or broadly ovate, 1--4 × 1.5--5 cm, papery or herbaceous, glabrous or abaxially puberulent, base broadly cordate, central lobe cuneate or rhombic, 3-lobed, lobules 1- or 2-denticulate or entire; lateral lobes obliquely broadly obovate or obliquely cuneate, unequally 2-lobed or 2-cleft to middle. Lower stem leaves similar to basal ones; upper stem leaves short petiolate, cuneate at base, 3-sect, segments oblanceolate. Compound monochasi um terminal, corymbose; bracts leaflike. Flowers 0.4--0.8 cm in diam. Pedicel 0.5--1.5 cm, glabrous or sparsely puberulent. Reeptacle puberulent or glabrous. Sepals 5, ovate-elliptic, 2--3 mm, abaxially appressed puberulent or glabrous. Petals 5, obovate, 2.2--4.5 × 1.4--2.4 mm, nectary pit without a scale, apex rounded. Stamens 10--19; anthers ellipsoid. Aggregate fruit cylindric, 3--11 × 1.5--4 mm; carpels numerous. Achene slightly bilaterally compressed, obliquely obovoid, 1--1.1 × 0.8--1 mm, glabrous, sometimes transversely 2- or 3-rugose, somewhat turgid along sutures; stigmas persistent, ca. 0.1 mm. Fl. Jan--Jul.

Europe, C. Asia, Himalaya, N. India, Siberia, Mongolia, China, Japan, N. America.

Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Henan, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Nei Mongol, Ningxia, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Xinjiang, Yunnan, Zhejiang [Afghanistan, Bhutan, N India, Japan, Kazakhstan, Korea, Nepal, N Pakistan, Russia (Siberia), Thailand; SW Asia, Europe, North America].

800-1700 m

By streams or lakes, paddy fields, wet grassy places; 50--2300 m.

Hecatonia scelerata (Linnaeus) Fourreau

Hecatonia palustris Loureiro; Ranunculus holophyllus Hance; R. oryzetorum Bunge; R. sceleratus var. sinensis H. Léveillé.