Ranunculus subg. Batrachium
Proc. Amer. Acad. Arts 21: 363. 1886.
Plants glabrous (or sheathing leaf bases sometimes pubescent). Stems creeping or floating, not bulbous-based, without bulbils. Roots nodal, never tuberous. Leaves cauline, either simple and laminate (with expanded blade), or completely dissected into filiform segments, or with proximal leaves filiform-dissected and distal leaves laminate; laminate leaves petiolate, undivided or 3-parted, segments entire to shallowly cleft and crenate; filiform-dissected leaves petiolate or sessile. Inflorescences axillary, solitary flowers. Flowers pedicellate; sepals deciduous soon after anthesis, 5; petals 5, white or white with yellow claws; nectary scale attached on 3 sides, forming ridge or shallow pocket not covering nectary, glabrous, free margin entire; style present. Fruits achenes, 1-locular; achene body ellipsoid or flattened-ellipsoid, 1-2 times as wide as thick, not prolonged beyond seed; wall thick, with coarse transverse ridges; margin low narrow ridge; beak much shorter than achene body.
Widespread except lowland tropics.
Species ca. 15 (3 in the flora).
Unlike most species of Ranunculus, members of this subgenus are not poisonous.
|1||Leaves all dissected into filiform segments.||Ranunculus aquatilis var. diffusus|
|1||Leaves not all filiform-dissected, all or some laminate and shallowly to deeply 3-lobed or -parted.||> 2|
|2||Leaves all laminate, margins shallowly crenate-lobulate, segments rounded; e North America.||Ranunculus hederaceus|
|2||Leaves of 2 types: laminate and filiform-dissected (filiform-dissected leaves sometimes few and inconspicuous in R. lobbii); laminate leaves 3-parted, segments elliptic, obovate, or fan-shaped; w North America.||> 3|
|3||Receptacle glabrous; style 1–1.5 mm.||Ranunculus lobbii|
|3||Receptacle hispid; style 0.1–0.8 mm.||Ranunculus aquatilis var. aquatilis|