Buttercups comprise about 275 different species. Most grow in bogs or moist areas, some in drier meadows. At Eloise Butler there are Buttercups in the Woodland Garden near and in the wetland and also in the Upland Garden.
The Tall Buttercup is an introduced species, a naturalized perennial, that has erect stems with soft hair, 1 to 3 feet high, with branching in the upper portion. Stems do not root at nodes.
The leaves are compound, basal and stem leaves vary in size, with the larger basal leaves divided into 3 to 5 sessile lobes which are deeply cleft or toothed, and on long stalks, as much as 8 inches long. Stem leaves have just a few simple segments and short stalked except the most upper which are stalkless. All leaf stalks are hairy. Leaves are usually all below the middle of the stem.
Inflorescence: Flowers occur in loose branching groups at the top of stems.
The flowers have 5 golden yellow shining petals and are from 2/3 to 1 1/4 inches wide when open; there are 5 greenish-yellow spreading sepals which have fine hair and fall away during flowering. The petals are broadly roundish and twice to 3x as long as the sepals. Nectaries are at the base of the petals. The center of this buttercup flower is a mass of stamens (30 to 70) with yellow anthers which surround a green immature receptacle composed of numerous carpels (15 to 40) each with a short style. This receptacle is not hairy. It blooms later than the other 3 buttercups in the Garden, usually late May to late summer.
Seed: The carpels mature to dry brown globose achenes 2-3 × 1.8-2.4 mm, that have margins forming a narrow rib. The tip has a persistent short triangular shaped beak that can be either curved or straight. Buttercup seeds need some cold stratification for germination, at least 30 days and some species require 60 days.
Toxic: Buttercups have hazardous properties - see notes below.
Habitat: Tall Buttercup grows from a short rhizome or caudex, the base of the plant is not bulbous. It is found in old fields, roadsides, meadows, and tended areas that are infrequently cut. It prefers sun but will grow and flower in partial sun. The plant can become weedy as the rhizome can create offshoots. New plants usually flower the second year.
Names: Ranunculus acris 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, acris, is from the Latin for 'sharp tasting' and probably was used to describe this species as it is one of the most acrid of the genus. See notes below. The family name of Buttercup, used to be "Crowfoot', hence the continuation of the old name in many of the species common names. The name "European" Buttercup has been used as this is a world-wide species, originating in Eurasia. The author name for the plant classification, 'L.' refers to Carl Linnaeus (1707-1778), Swedish botanist and the developer of the binomial nomenclature of modern taxonomy.
Comparisons: While the tall flower stalks make this species recognizable, here are a few other buttercups for comparison: Kidney-leaf Buttercup, R. abortivus; Swamp Buttercup, R. hispidus; Cursed Crowfoot, R. sceleratus; Hooked Crowfoot, R. recurvatus; and Bristly Buttercup, R. pensylvanicus.
Above: The tall branched stalks of the inflorescence of Tall Buttercup. Drawing courtesy Kurt Stüber's Online Library.
Below: 1st photo - The typical shining Tall Buttercup flowers. 2nd photo - Note the green group of carpels showing in the right-hand flower.
Below: 1st photo - more detail of the stamens and receptacle carpels. 2nd photo - The sepals are much smaller than the petals and have fine hair.
Below: 1st photo - The lower leaf with its long stalk. 2nd photo - The upper leaves which have a less complex design.
Below: 1st photo - The maturing seed head; 2nd photo - The individual globose seeds which have a short triangular beak.
Below: A grouping of Tall Buttercup along the Goldenrod Trail in the Upland Garden. All photos - June.
Notes: A native of Europe it is now naturalized in much of Eastern Minnesota down through the metro area counties plus a few counties in the SE Corner. The plant was included on Eloise Butler's early list of indigenous plants in the Garden area - she first noted it in her log on June 30, 1917 when she found one in bloom. Martha Crone included it on her 1951 Garden Census, she had planted the species in 1948. There are also native varieties of Buttercup in Minnesota, including 3 within the Garden, R. hispidus, R. abortivus, and R. recurvatus. R. acris is one of 16 buttercup species found in Minnesota. In North America R. acris is found throughout except for 7 states of the south central U.S.
Toxicity: Many of the species of Buttercup are poisonous and will severely irritate the skin. If taken internally the plant can cause stomach inflammation. R. acris has acrid and poisonous juices which can be fatal to browsing animals in the spring when the leaves are young and they eat a lot of them causing inflammation of the mouth and digestive tract; this is caused by the glycoside ranunculin. Cattle can be affected if they eat the plant but they normally refuse it which explains Eloise Butler's comment given below about being a pest of the hayfields. Milk from cows who have eaten the plant will have a bitter taste. When the plant is dried, however, the poisonous material evaporates. [Note: Ranunculin in moist plant tissue breaks down to the toxin protoanemonin, which is what causes the tissue damage. This has also been linked to the poisoning of bees who had taken in Buttercup pollen - see this article on bees - pdf. and this article on Ranunculin and Anemonol - 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 Notes: On April 30, 1911, Eloise Butler published an article in Minneapolis Sunday Tribune in which she discussed Buttercups. Here is what she wrote:
"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 [her text omits the common name] blooms 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." [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"