Harvey’s Buttercup (Ranunculus harveyi var. harveyi*) of the Buttercup (Ranunculaceae) family has an open structure and a succulent appearance. The genus name, based on Latin words for “frog” (rana) and “little” (unculus) relates to the occurrence of many buttercups in moist habitats. The specific epithet honors Francis LeRoy Harvey, faculty member of the Arkansas Industrial University from 1876-1885, who first described the species. In the US, it occurs primarily in a broad swath from southeast Oklahoma, across Arkansas and the southeastern half of Missouri – along with widely scattered populations in several neighboring states. In Arkansas, Harvey’s buttercup is found across the Ozark Plateaus, River Valley and Ouachita Mountains – along with a few scattered counties in the southeast. Habitat includes partially to mostly sunny sites with well-drained rocky to sandy soils in upland forests and savannas.
The perennial plant has a stubby root crown supported by long, white, spreading fibrous roots and white, elongate, carrot-like, descending, smooth roots. New basal leaves appear in late fall and remain over winter. The firm, shiny, orbicular to kidney-shaped leaves have prominent cordate bases and long petioles (leaf stalks). Outer leaves tend to be prostrate (lying flat on the ground), while inner leaves tend to be ascending. Blades of young leaves are depressed at the petiole but become planar with maturity. Blade margins are broadly scalloped from the apex to the cordate base. Broadest scallop is at the leaf apex with the lateral 3-4 scallops decreasing in width toward the cordate base. Center of scallops on robust plants is marked by a tiny tip. Side-margins of scallops may overlap slightly as leaves transition to lower basal leaves with 3 lobes and/or 3 leaflets. Basal leaves are to 1¾ inches long and 1¼ inches wide with “depth” of cordate base being up to ¼ inch. Slender reddish petioles, to 2½ inches long and 1/16 inch wide, have a central groove along their upper side extending onto the blade. Petioles may be glabrous or have sparse, fine, ascending hairs alongside their central grooves. Blades of young leaves are medium green above and whitish pale-green below with lower surface becoming green with leaf maturity. Palmate veins, radiating from the petiole to blade margins, are slightly expressed above and recessed below. Basal leaves fade as flowering progresses into spring.
Stems (directly from root crown), along with primary branches (from axillary leaf buds on stem), are topped with flower buds when they emerge in mid-winter. The erect to spreading stems (one to several) grow to a final height of 6 inches to 1½ feet. Primary branches, set at 45⁰ from stems and spreading, also bear leaves which may subtend secondary branches. The longest primary branches, to 9 inches on robust plants, are lowest on the stem and often reach the same height as the central stems. The lower ⅓ to ¼ of stems and branches tend to be leafless and distal leaves are small to minute. This makes the plants look open and airy. The terete, pale-green, succulent-appearing stems and branches are hollow. They appear to be glabrous, but have sparse, relatively long, fine, ascending hairs, especially in their lower portion. The herbaceous stems and branches wither away after the growing season.
Lowermost stem leaves of more robust plants may have 3 leaflets on petiolules (trifoliate compound) or may have 3 sessile lobes. Leaflets of trifoliate leaves tend to be broadly wedge shaped (cuneate) with straight side margins and crenulated apexes. Lobes of 3-lobed leaves tend to be narrowly cuneate with truncated apexes. At mid-stem and on branches, leaves have elongate-oblong sessile lobes changing, distally, from 3-lobed to 2-lobed and then a simple leaf with a single elongate-oblong blade. More distal leaves become increasingly small to tiny and lanceolate with the final leaf subtending the pedicel (stalk of flower). A few fine hairs may be scattered on the upper surface of leaf blades. Venation of elongate-oblong leaflets and lobes is pinnate with secondary veins extending toward leaf apex. Less robust and smaller plants may lack both trifoliate and 3-lobed leaves.
Spherical, knobby flower buds are protected by 5 thin, triangular, tightly clasping, green sepals (calyx). Flowering begins with the most distal buds as branching (and bud formation) continues. Each flower remains “open” for about 3 days with the flowering period extending from late February into April. Flowers have 5-7 petals in a single layer which may be well-spaced (5 petals) to crowded (8 petals). A typical flower has 5 sepals positioned between 5 petals, but number of sepals and size also varies. Sepals are glabrous or may have sparse long, fine hairs on their exterior. At anthesis, the now-yellowish-green and boat-shaped (naviculate) sepals are mostly hidden by petals. A tight, multi-layered ring of stamens (filaments + anthers) surrounds a spherical receptacle. Receptacle is densely covered with bright yellowish-green, exposed pistils (ovary + style + stigma). Planar, oblong petals are twice as long as sepals; shiny, smooth yellow above and a dull yellow below. Stamens (androecium), attached on a short floral axis between receptacle and petals, have thin filaments and relatively large 2-lobed yellow anthers. Pistils (gynoecium) have relatively large, flattened ovaries, tipped with a very short, straight to hooked style and a microscopic stigma. Flowers attach to short (⅛ inch) to long (1⅜ inch) glabrous, terete pedicels which are the same pale-green as branches and stems. Flowers and pedicels are glabrous.
Fertilized ovaries enlarge to form flattened, ovoid, 1/16 inch long, glabrous achenes with a short persistent style/stigma (apex). Apex may be straight to slightly hooked. Sepals, petals and stamens drop-off to leave a globose head (less than ¼ inch long) of developing achenes. After achenes drop-off, a slightly elongated, pale-green, bumpy, glabrous to sparsely hairy receptacle remains.
As a volunteer-plant in a garden or natural setting, Harvey’s Buttercup can add a spot of green overwinter and shiny yellow flowers in spring. This buttercup may be the first to bloom. Flower size is intermediate between the “small-flowered buttercups” (see next paragraph) and large-flowered buttercups such as, Early Buttercup (R. fascicularis) and Hispid Buttercup (R. hispidus var. hispidus). Pollen and nectar attract various bees and flies. Seed eaten by game birds and small mammals. Not noted to spread aggressively by seed.
- Two of the other 17 species of buttercups in Arkansas have a similar appearance to Harvey’s buttercup in terms of basal leaf shape, overall plant structure, and yellow flowers: Kidney Leaf or Small Flowered Buttercup (R. abortivus) and Rock or Small Flowered Buttercup (R. micranthus). R. abortivus can be distinguished by its smaller flowers, glabrous stems and pubescent receptacle. R. micranthus can be distinguished by its smaller flowers, truncate to cuneate basal leaves, villous stems and glabrous receptacle.
Article and photographs by ANPS member Sid Vogelpohl
