Plants glabrous or sometimes pilose or pubescent. Stems erect, not bulbous-based, without bulbils. Roots basal, sometimes tuberous. Leaves basal and cauline, simple or compound; basal leaves petiolate, blades variously divided, unlobed to deeply parted, compound, or filiform-dissected, segments undivided or again lobed or parted, margins entire or crenate, never serrate; cauline leaves sessile to nearly sessile or sometimes with much shorter petioles than basal leaves, blades lobed to compound or dissected (rarely unlobed in R. macauleyi and R. glaberrimus). Inflorescences 1-50-flowered cymes. Flowers pedicellate; sepals deciduous soon after anthesis, 5; petals yellow (rarely absent in R. pedatifidus); nectary scale joined with petal on 3 sides, forming pocket enclosing nectary (sometimes with apex free, forming flap shorter than pocket), glabrous or setose, free margin entire or fringed; style present. Fruits achenes, 1-locular; achene body thick-lenticular or asymmetrically thick-lenticular to compressed-globose, 1.2-2 times as wide as thick, not prolonged beyond seed; wall thick, smooth; margin low narrow ridge, often inconspicuous; beak much shorter than achene body.


Worldwide except lowland tropics.


Species ca. 70 (22 in the flora).

Selected References



1 Abaxial surface of sepals with dense brown pubescence. > 2
1 Abaxial surface of sepals glabrous or with colorless hairs. > 4
2 Basal leaf blades narrowly elliptic to lanceolate or oblanceolate; s Rocky Mountains. Ranunculus macauleyi
2 Basal leaf blades orbiculate to reniform; Canadian Rocky Mountains and Arctic. > 3
3 Receptacle brown-pilose; basal leaf blades usually shallowly lobed, or unlobed with crenate margins. Ranunculus sulphureus
3 Receptacle glabrous; basal leaf blades 3-parted. Ranunculus nivalis
4 Basal leaves deciduous before anthesis; nectary scale ciliate, petals 2–3 times as long as wide. Ranunculus arizonicus var. arizonicus
4 Basal leaves persistent; nectary scale glabrous, (glabrous or ± pilose in R. cardiophyllus and R. glaberrimus, which have petals 1–1.5 times as long as wide). > 5
5 Some or all basal leaf blades unlobed. > 6
5 All basal leaf blades lobed or parted. > 14
6 Basal leaf margins entire or with 3 broad shallow rounded teeth; heads of achenes globose, 6–20mm wide. Ranunculus glaberrimus
6 Basal leaf margins either crenate to crenate-lobulate, with more than 5 rounded teeth, or innermost teeth lobed or divided; heads of achenes usually ovoid to cylindric (sometimes globose and 3–8 mm wide). > 7
7 Petals 1–3.5 mm. > 8
7 Petals 4–18 mm. > 10
8 Stems villous, sometimes sparsely so; receptacle glabrous; base of some roots ± swollen and tuberous, usually 1–2 mm thick; leaf base usually obtuse or truncate. Ranunculus micranthus
8 Stems glabrous; receptacle pilose, sometimes sparsely so; base of roots never much swollen, 0.2–1.5 mm thick; leaf base ± cordate. > 9
9 Sepals hispid; achene beak 0.6–1 mm. Ranunculus allegheniensis
9 Sepals glabrous; achene beak 0.1–0.2 mm. Ranunculus abortivus
10 Leaf blades wider than long; e of Great Plains, not in Great Lakes area. > 11
10 Leaf blades at least as long as wide; Great Lakes area and Great Plains w to Great Basin. > 12
11 Pedicels glabrous (see also R. escholtzii with lobed leaves); se United States. Ranunculus harveyi var. harveyi
11 Pedicels pubescent, sometimes sparsely so; e Canada. Ranunculus allenii
12 Sepals 5–8 × 3–7 mm; nectary scale ciliate, sometimes glabrous; leaf base cordate to broadly obtuse. Ranunculus cardiophyllus
12 Sepals 3–6× 1.5–3mm; nectary scale glabrous; leaf base obtuse or acute to rounded. > 13
13 Basal leaf blades ovate, obovate, or orbiculate; heads of achenes cylindric, 7–17 mm; achene beak 0.4–2 mm; Rocky Mountains, Great Basin, and Black Hills. Ranunculus inamoenus
13 Basal leaf blades ovate to rhombic; heads of achenes depressed-globose, 4–6 mm; achene beak 0.2– 0.3 mm; n Great Plains and eastward. Ranunculus rhomboideus
14 Basal leaf blades dissected into linear segments. > 15
14 Basal leaves at most 1×-divided, segments not linear. > 16
15 Roots slender, 0.8–1.4 mm thick; achene beak 1.2–1.7 mm. Ranunculus adoneus
15 Roots 2–3 mm thick; achene beak 0.8–1.5 mm. Ranunculus triternatus
16 Some roots clavate and tuberous, 2.5–5 mm thick; basal leaf blades deeply divided into 3 oblanceolate segments. Ranunculus jovis
16 Roots not clavate or tuberous, 0.1–1.6 mm thick; leaves various but not as above. > 17
17 Petals 7–15 mm. > 18
17 Petals 1–8 mm. > 20
18 Pedicels glabrous. Ranunculus eschscholtzii
18 Pedicels pubescent. > 19
19 Heads of achenes globose to short-ovoid; basal leaves 3-parted with segments again lobed or parted, margins toothed; Greenland. Ranunculus auricomus
19 Heads of achenes cylindric; basal leaves pedately (5–)7(–9)-parted or -divided, segments sometimes again lobed, margins never toothed; throughout n North America. Ranunculus pedatifidus var. affinis
20 Flowering stems 0.6–3.5 cm (sometimes longer in fruit); petals 1–3.5 mm. Ranunculus pygmaeus
20 Flowering stems (1–)4–15(–27) cm; petals 3–8 mm. > 21
21 Petals 6–16 mm; beak of achene straight, 0.6–1.8 mm; pedicels glabrous. Ranunculus eschscholtzii
21 Petals 4–8 mm; beak of achene straight or curved, 0.3–0.7 mm; pedicels glabrous or pilose. > 22
22 Base of basal leaves obtuse; petals 5–8 mm; arctic Alaska, Canada, and Greenland. Ranunculus sabinei
22 Base of basal leaves nearly cordate to truncate; petals 4–5 mm; Alaska, Yukon, and Rocky Mountains. Ranunculus gelidus