Gmelin's Buttercup

Ranunculus gmelinii has been divided into varieties on the basis of indument and flower size. These characters are variable and poorly correlated with one another, however, and these varieties scarcely seem natural.

Stems prostrate or sometimes floating, glabrous or hirsute, rooting nodally. Leaves: basal leaves absent, cauline leaf blades reniform to circular, 3-parted, 0.6-6.5 × 1.1-9 cm, base cordate, segments again 1-3×-lobed to -dissected, margins entire or crenate, apex rounded to filiform. Flowers: receptacle sparsely hispid; sepals 4-5, spreading or reflexed from base, 2-5 × 2-4 mm, glabrous or sparsely pilose; petals 4-14, 3-7 × 2-5 mm; nectary scale variable, crescent-shaped, funnel-shaped, or flaplike; style 0.2-0.4 mm. Heads of achenes globose or ovoid, 3-8 × 3-7 mm; achenes 1-1.6 × 1-1.2 mm, glabrous; beak narrowly lanceolate or filiform, 0.4-0.8 mm. 2 n = 16, 32, 64.

Herbs perennial, subaquatic. Roots fibrous, subequally thick. Stems elongated, glabrous or appressed puberulent above, short branched, often rooting at nodes. Stem leaves with petiole 0.5--2 cm, glabrous or sparsely puberulent; blade 3-partite near base, orbicular-reniform or cordate-pentagonal, 0.4--1 × 0.6--1.7 cm, herbaceous, subglabrous or abaxially sparsely appressed puberulent, base cordate, central lobe cuneate-rhombic, 3-lobed; lateral lobes obliquely obovate or obliquely flabellate, unequally 2-partite, ultimate lobules narrowly ovate or linear-lanceolate. Monochasium terminal, 1--4-flowered; bracts subsessile, leaflike or undivided, narrowly ovate, 0.5--7 mm. Flowers 0.4--0.9 cm in diam. Pedicel to 3.5 cm, glabrous or sparsely puberulent. Receptacle sparsely puberulent. Sepals 5, ovate-elliptic, 2.2--3 mm, glabrous. Petals 5, narrowly obovate or obovate, 2.2--4 × 1.5--2.5 mm, nectary pit without a scale, apex rounded. Stamens 12 or numerous; anthers ellipsoid. Aggregate fruit subglobose, 3--4 mm in diam.; carpels numerous. Achene broadly ellipsoid or obliquely obovoid, 1--1.3 × 0.8--1 mm, glabrous, margin with corky thickening; style persistent, ca. 0.3 mm. Fl. Jun--Aug, fr. Sep.

Alta., B.C., Man., N.B., Nfld., N.W.T., N.S., Ont., P.E.I., Que., Sask., Yukon; Alaska, Colo., Idaho, Ill., Iowa, Maine, Mich., Minn., Mont., Nev., N.Mex., N.Dak., Oreg., Utah, Wash., Wis., Wyo.; Eurasia.

Flowering spring-summer (May-Sep).

Shallow water or drying mud, wet meadows, swamps, marshes, ponds, shores of rivers; 0-2800m.

Streams, moist places by streams, meadows. Heilongjiang, Jilin, NE Nei Mongol [Japan, Mongolia, Russia (Siberia); N Europe].

Ranunculus gmelinii subsp. purshii (Richardson) Hultén; R. gmelinii var. hookeri (D. Don) L. D. Benson; R. gmelinii var. limosus (Nuttall) H. Hara; R. gmelinii var. prolificus (Fernald) H. Hara; R. purshii Richardson

Ranunculus gmelinii, Gmelin's buttercup or small yellow water-crowfoot, is a species of flowering plant in the buttercup family, Ranunculaceae. It is native to northern North America, where it occurs across Canada and the northern and higher-elevation regions of the United States. It is also present in Eurasia.

This species is a perennial herb growing prostrate stems on moist ground or floating stems in shallow water. It is hairy to hairless. The leaf blades are round or kidney-shaped and are divided into three parts that may be subdivided. The yellow petals are 4 to 14 millimeters long. Ranunculus gmelinii occurs in wetland habitats and on shorelines.

The plant is not a threatened species, but it becomes rare in the habitat on the edges of its range; it is protected as a threatened plant in the state of Maine, and var. hookeri is a state-listed endangered plant in Wisconsin. It is listed as an endangered species in Newfoundland and Labrador.

This species was named in honor of Johann Georg Gmelin (1709-1755).