Ranunculus recurvatus is a native erect perennial forb growing 8 to 24 inches tall with occasional branching. Stems have long whitish spreading hair and some purplish appendages at the bulbous base of the stem.
Leaves are both basal and stem, much the same shape. Basal leaves are stalked, palmate, with 3 to 5 deep lobes, broadly heart shape in outline, with the leaf segments undivided or shallowly cleft. Leaf segment margins have rounded teeth. Stem leaves look similar, but smaller with shorter stalks. Upper leaves will be stalkless and usually with 3 lobes. Leaf surfaces are dark green on top with some spares hair and paler under with much fine whitish hair.
The inflorescence is a loose cluster of flowers at the top of stems.
Flowers are small 5-part with five yellow petals that are thinly oblong and about the same length as the 5 yellow-green sepals, which have fine hair. The sepals reflex near the base when the flower is in bloom. At the base of the petals is a ring of numerous stamens with yellow anthers which surround a green receptacle of pistils with short styles. Each flower is only 1/3 to 1/2 inch wide and flower stalks have fine hair. The nectary is in a pocket at the base of the petals.
Seed: When fertile, the receptacle elongates to a globoid shape and produces a dense cluster of dry achenes that are flat sided, 1.6-2.2 × 1.4-1.8 mm in size, with a curved hooked beak. Buttercup seeds need some cold stratification for germination, at least 30 days and some species require 60 days.
Toxic: Buttercups have several hazardous parts - see notes below.
Habitat: Buttercups comprise about 275 different species. Hooked Crowfoot grows in swamps, mesic woods, along stream banks in rich soil with wet to moist conditions, partial sun to light shade preferred. It roots from a bulbous corm-like base. In an early spring, a bloom can occur as early as late April.
Names: Ranunculus recurvatus is in Ranunculus Sect. Ranunculus. The generic name Ranunculus, is from two Latin words, 'rana' meaning ' frog' and 'unculus' meaning 'little' and together they refer to a group of plants, many of which grow in moist places - like little frogs. The species, recurvatus, means 'recurved' such as are the beaks of the dry achenes of this species. The family name of Buttercup, used to be "Crowfoot', hence the continuation of the old name in many of the species common names. The author name for the plant classification, ‘Poir.’ is for Jean Louis Marie Poiret (1755-1834) French clergyman, botanist and explorer and Professor of Natural History at the Ecoles Centrale of Aisne. The variety recurvatus has been assigned as the North American type of this species. There is one other variety in the world outside of North America.
Comparisons: Here are a few other buttercups for comparison: Kidney-leaf Buttercup, R. abortivus; Swamp Buttercup, R. hispidus; Tall Buttercup, R. acris; Bristly Buttercup, Ranunculus pensylvanicus; Cursed Crowfoot, R. sceleratus. The flower of R. recurvatus most closely resembles that of R. abortivus.
Above: The inflorescence and the full plant.
Below: 1st photo - As flowers mature, the carpels in the center of the flower elongate, forming the distinctive hook at the tip. 2nd photo - The yellow-green sepals are in reflexed position when the flower is open. The yellow petals are about the same length but much narrower - slightly wider than the anthers of the stamens.
Below: 1st photo - A lower stalked leaf. The upper stem leaves are sessile. 2nd photo At the base of the hairy stems are some purplish appendages.
Below: 1st photo - The flower head changes to a globoid shape and produces a dense cluster of dry achenes that are flat sided with a curved hooked beak. 2nd photo - The achenes turn to a brown color when fully mature.
Below: 1st photo - The underside of the leaf is a paler color due to dense fine hair. 2nd photo - The upper surface is darker green with sparse surface hair. 3rd photo - The stem is green with fine ridges and spreading whitish hairs.
Notes: While not listed on either Eloise Butler's list of indigenous plants, nor on Martha Crone's 1951 Garden census, it is now one of 4 buttercups in the Garden and has been present at least since the 1980s. It occurs in about 2/3rds of Minnesota, mostly the eastern half of the State. Absent in most of the western part of the state. In North America, its range is the eastern half of the continent. It is one of 16 buttercup species found in Minnesota. There are two varieties of this species but the only one in North America is var. recurvatus.
Toxicity: Many of the species are poisonous and will severely irritate the skin. If taken internally the plant can cause stomach inflammation. Cattle can be affected if they eat the plant. When the plant is dried, however, the poisonous material evaporates. Bees have been poisoned when they pick up pollen from Ranunculus species. - see this article on bees - pdf.
Legend: The legend of this plant family is this: Ranunculus, a Libyan boy who sang very beautifully, always wore green and gold silk. While singing in the woods, wood nymphs heard him and to get some peace and quiet, they turned him into a green and gold flower.
Eloise Butler wrote the following about Buttercups: "A number of the early flowering plants are members of the crowfoot family [Ranunculaceae -in current times this family is now called the Buttercup Family], [such] as the anemones and buttercups. In the divided leaves of a crowfoot, as some of the buttercups are called, the early botanists saw a resemblance to a bird’s foot. The buttercups of Minnesota are not so much in evidence as the tall European buttercup [Ranunculus acris L.] the pest of the hay fields - farther east.
One early species, Ranunculus abortivus, [Littleleaf Buttercup] has so small a flower that a novice would scarcely notice it, and is surprised to hear it named a buttercup. Neither would a child be likely to apply the time-worn test of holding the flower to your face to learn if you love butter. This lowly buttercup blooms [her text omits the common name] sparsely on the prairie with the pasque flower. The specific name rhomboideus [prairie buttercup] indicates the shape of the leaf. The low, tufted R. fascicularis [early buttercup] has a larger flower, but is not conspicuously massed. Our two prettiest buttercups are aquatics - one with shining, yellow petals; the other with smaller white flowers and long, railing stems; and both bearing finely dissected leaves.
The large Crowfoot family is without strongly marked characters. Its plants have usually an acrid taste; the leaves are generally more or less cut or divided; the corolla is often wanting, and, when this is the case, the calyx is colored like a corolla; the stamens are numerous; the pistils vary in number from one to several; and all the parts of the flower are distinct or unconnected." Published April 30, 1911, Minneapolis Sunday Tribune [Entire Article]
References: Plant characteristics are generally from sources 1A, 32, W2, W3, W7 & W8 plus others as specifically applied. Distribution principally from W1, W2 and 28C. Planting history generally from 1, 4 & 4a. Other sources by specific reference. See Reference List for details.
Identification booklet for most of the flowering forbs and small flowering shrubs of the Eloise Butler Wildflower Garden. Details Here.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"