Ranunculus sect. Hecatonia
basal and usually also nodal, never tuberous.
creeping (erect in Ranunculus sceleratus), not bulbous-based, without bulbils.
all cauline or both basal and cauline;
basal and lower cauline leaves similar, petiolate, blades lobed to divided or (submerged leaves) deeply dissected, segments undivided or lobed.
2-25-flowered cymes or axillary solitary flowers.
pedicellate;
sepals deciduous soon after anthesis, 3-5;
petals 3-14, yellow;
nectary scale variable, forming crescent-shaped ridge surrounding but not covering nectary, or funnel-shaped tube surrounding nectary, or distal margin of funnel expanded to form large flap, then nectary sometimes displaced onto flap, glabrous, free margin entire;
style present or absent.
achenes, 1-locular;
achene body thick-lenticular or compressed-ellipsoid to discoid, 1.2-3 times as wide as thick, not prolonged beyond seed;
achene wall thick, smooth or with weak transverse wrinkles, glabrous;
margin a thick, low or high corky band or ridge;
beak much shorter than achene body or sometimes absent.
Ranunculus sect. Hecatonia
Species ca. 15 (4 in the flora).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Stems erect, rooting only at base (very rarely also at proximal nodes). | R. sceleratus |
1. Stems prostrate and rooting at nodes, or floating and rootless. | → 2 |
2. Leaf blades 0.3–1.2 cm, deeply 3-lobed or -parted, terminal segment entire or distally crenulate; nectary-scale low crescent-shaped ridge surrounding nectary; style 0.1–0.2 mm. | R. hyperboreus |
2. Leaf blades 0.6–7.3 cm, 3-parted, terminal segment again lobed or dissected; nectary-scale a free flap, nectary on surface of flap; style 0.2–1.2 mm. | → 3 |
3. Styles 0.2–0.4 mm in flower; achenes 1–1.6 mm, beaks 0.4–0.8 mm; petals 3–7 mm | R. gmelinii |
3. Styles 0.8–1.2 mm in flower; achenes 1.8–2.2 mm, beaks 1–1.8 mm; petals 7–12 mm. | R. flabellaris |
