[Ranunculus repens var. degeneratus Schur, moreRanunculus repens var. erectus DC., Ranunculus repens var. glabratus DC., Ranunculus repens var. linearilobus DC., Ranunculus repens var. pleniflorus Fernald, Ranunculus repens var. typicus G. Beck, Ranunculus repens var. villosus Lamotte]
Stems decumbent or creeping, rooting nodally, hispid to strigose or almost glabrous, base not bulbous. Roots never tuberous. Basal leaf blades ovate to reniform in outline, 3-foliolate, 1-8.5 × 1.5-10 cm, leaflets lobed, parted, or parted and again lobed, ultimate segments obovate to elliptic or sometimes narrowly oblong, margins toothed, apex obtuse to acuminate. Flowers: receptacle hispid or rarely glabrous; sepals spreading or reflexed from base, 4-7(-10) × 1.5-3(-4) mm, hispid or sometimes glabrous; petals 5(-150), yellow, 6-18 × 5-12 mm. Heads of achenes globose or ovoid, 5-10 × 5-8 mm; achenes 2.6-3.2 × 2-2.8 mm, glabrous, margin forming narrow rib 0.1-0.2 mm wide; beak persistent, lanceolate to lance-filiform, curved, 0.8-1.2 mm. 2 n = 14, 32. Flowering late winter-summer (Mar-Aug). Meadows, borders of marshes, lawns, roadsides; 0-2500 m; introduced; Greenland; St. Pierre and Miquelon; Alta., B.C., N.B., Nfld., N.S., Ont., P.E.I., Que., Yukon; Ala., Alaska, Ark., Calif., Conn., Del., D.C., Idaho, Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., Mont., Nebr., Nev., N.H., N.J., N.Y., N.C., Ohio, Oreg., Pa., R.I., S.C., S.Dak., Tenn., Tex., Utah, Vt., Va., Wash., W.Va., Wis., Wyo.; Central America; South America; native to Eurasia; Pacific Islands; Australia. Ranunculus repens is widely naturalized in many parts of the world. Plants with sparse pubescence have been called R . repens var. glabratus . Horticultural forms with the outer stamens transformed into numerous extra petals occasionally become established and have been called R . repens var. pleniflorus . These variants have no taxonomic significance.
Hirsute to strigose or subglabrous perennial, mostly creeping, rarely ascending or erect; lvs petioled, 3-parted, the terminal segment stalked, all segments broadly obovate to subrotund, cleft or lobed, sharply toothed; pet 8-15 mm, two-thirds as wide; anthers 1-2 mm; achenes broadly and obliquely ovate, 2.5-3.5 mm, sharply but narrowly margined, the beak triangular, usually curved, 0.8-1.5 mm; 2n mostly =32. Native of Europe, naturalized in fields, lawns, roadsides, and wet meadows. May-July. Robust, subglabrate plants have been called var. glabratus DC., and double- flowered ones have been called var. degeneratus Schur or var. pleniflorus Fernald.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.