Ranunculus micranthus Nutt.
Family: Ranunculaceae
Rock Buttercup
[Ranunculus micranthus var. cymbalistes (Greene) Fernald,  more...]
Ranunculus micranthus image

Stems erect, 11-40 cm, villous, each with 8-35 flowers. Roots dimorphic, some filiform, 0.2-0.6 mm thick and some with tuberous bases 1-2 mm thick. Basal leaves persistent, blades ovate, orbiculate, or transversely elliptic, outer blades undivided, inner 3-parted or 3-foliolate, 1-3.3 × 1-3 cm, base truncate to broadly obtuse or sometimes weakly cordate, margins crenate, apex rounded-obtuse. Flowers: pedicels glabrous or villous; receptacle glabrous; sepals 2-4 × 1-1.5 mm, abaxially glabrous or pubescent, hairs colorless; petals 5, 1.5-3.5 × 0.5-1.5 mm; nectary scale glabrous. Heads of achenes globose to cylindric, 3-7 × 2-4 mm; achenes 1.1-1.5 × 1-1.3 mm, glabrous; beak subulate, straight or curved, 0.2-0.3 mm. 2 n = 16.

Flowering spring (Mar-May). Woods, meadows, and clearings; 0-1000 m; Ala., Ark., Conn., D.C., Ill., Ind., Kans., Ky., Md., Mass., Miss., Mo., N.J., N.Y., N.C., Ohio, Okla., Pa., S.Dak., Tenn., Va., W.Va.

From Flora of Indiana (1940) by Charles C. Deam

There are seven reports for this species, all from the southern half of the state. My specimens are from near the bases of slopes wooded with sugar maple and from the crests of wooded ridges. It is either very local or so inconspicuous that it is overlooked.

Much like no. 16 [Ranunculus pensylvanicus L.f.]; some of the roots conspicuously thickened; lvs sparsely villous with straight hairs 1-2 mm, the basal broadly ovate in outline, broadly cuneate to rounded or truncate at base, or a few occasionally subcordate; 2n=16. Dry or moist woods; Mass. to N.C. and W.Va.; s. O. to Tenn., w. to S.D. and Okla. Apr., May.

Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.

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