Flora of North America species comparison

never tuberous.

basal, sometimes also nodal, sometimes tuberous.

erect, never rooting nodally, strigose or hirsute, base bulbous and cormlike.

erect to decumbent, sometimes stoloniferous, sometimes bulbous-based, without bulbils.

basal and cauline, petiolate;

basal deeply parted or compound (except sometimes in R. orthorhynchus var. bloomeri), blades with segments lobed or parted, margins toothed;

cauline deeply parted or compound, similar to basal or with shorter petioles and/or blades with narrower segments (rarely poorly developed in R. fascicularis).

blades ovate to cordate in outline, 3-foliolate, rarely merely deeply divided, 2–5.3 × 2.4–5.4 cm, leaflets 1–2x-lobed, ultimate segments oblong to obovate, margins toothed, apex rounded in outline.

1-50-flowered cymes.

receptacle pubescent;

sepals reflexed 2–3 mm above base, 6–9 × 2–4 mm, pilose;

petals 5, yellow, 9–13 × 8–11 mm.

pedicellate;

sepals deciduous soon after anthesis, 5 (sometimes 6 in R. occidentalis var. hexasepalus);

petals always present, yellow, sometimes abaxially reddish, rarely poorly developed;

nectary scale attached basally, free from petal for at least 1/2 its length, forming flap covering nectary (or sometimes attached on 3 sides, forming pocket in R. recurvatus), glabrous, free margin entire;

style present.

achenes, 1-locular;

achene body discoid, strongly flattened, 3-15 times as wide as thick, not prolonged beyond seed;

wall thick, not ornamented;

margin low or high narrow ridge or wing;

beak much shorter than achene body.

ovoid, 6–9 × 5–7 mm;

achenes 2.2–3.2 × 2.2–2.8 mm, glabrous, margin forming narrow rib 0.1–0.2 mm wide;

beak persistent, lanceolate to deltate, 0.2–0.8 mm, slender tip hooked when present.