[Ranunculus hispidus var. eurylobus L.D.Benson, moreRanunculus hispidus var. falsus Fernald, Ranunculus hispidus var. greenmanii L.D.Benson, Ranunculus hispidus var. marilandicus (Poir.) L.D.Benson, Ranunculus septentrionalis Poir.]
Stems erect or decumbent, sometimes rooting nodally, hispid or strigose, base not bulbous. Roots never tuberous. Basal leaf blades ovate to deltate in outline, 3-foliolate or outer blades merely 3-parted, 2-13.4 × 2.4-16.8 cm, leaflets undivided to lobed or parted, ultimate segments narrowly elliptic or oblanceolate to circular, margins toothed, apex acuminate to rounded. Flowers: receptacle hispid; sepals spreading or reflexed, 4-10 × 2-5 mm, hispid; petals 5, yellow, 8-16 × 3-9 mm. Heads of achenes hemispheric to short-ovoid, 6-10 × 7-10 mm; achenes 2.2-5.2 × 2-3.8 mm, glabrous, margin forming narrow rib or broad wing 0.1-1.2 mm wide; beak persistent, lance-subulate, straight or somewhat curved, 0.8-2.6 mm. Until recently, the varieties of Ranunculus hispidus were usually treated as distinct species. Arguments for restoring species status to R . hispidus var. nitidus were given by G. L. Nesom (1993).
Fibrous-rooted perennial 1.5-9 dm, sometimes with some somewhat thickened but elongate (over 5 cm) roots; rhizome short, regenerated in part each year, only the oldest portion withering; basal lvs the largest, the blade at least as wide as long, mostly 3-lobed or trifoliolate, the acute or acuminate lobes or segments (especially the terminal one) variously incised, lobed, or merely toothed; pet 5-8(-10), widest above the middle, 8-14 נ3-10 mm, equaling or to twice as long as the sep; receptacle ±clavate or ellipsoid above the broad staminal zone; body of the achenes subrotund or obovate, 2-3.5 mm, the nerves bordering the marginal keel tending to be raised so that the margin is ±tricarinate, the keel sometimes winged; beak straight or nearly so, 1.8-3 mm; 2n=32, 64. N.S. and s. Que. to se. Sask., s. to Fla. and e. Tex. Apr., May. Three vars., with broadly overlapping ranges.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.