Rough-fruited Cinquefoil is an introduced plant that grows erect, 16 to 32 inches high, with hairy stems that are un-branched to the inflorescence.
Leaves are palmately divided and deeply lobed. The lower leaves are long stalked and have 5 to 7 leaflets and stipules; the upper are smaller, shorter stalked and have 3 leaflets. Leaflets have serrate edges and are much longer than wide and are hairy on the underside.
Inflorescence: Within the inflorescence many flowers can occur in flattened branched clusters.
Flowers are pale yellow, 5 parted, around 3/4 inches wide, with heart-shaped petals that have a deeper yellow color at the point of attachment. The receptacle is a brighter deeper yellow containing numerous styles of the pistils and surrounded by about 20 plus stamens that have yellow filaments and yellowish-brown anthers. The green sepals (calyx lobes) are triangular, shorter than the petals, and hairy. These are placed alternate with the petals so that they are partially visible between the petals. There are also 5 small green still shorter bracts under the sepals and placed directly beneath the petals.
Seed: The flowers produce a capsule containing a number of dry ridged ellipsoid shaped seed, about 1 mm long, without pappus, that is dispersed by wind action shaking the flowering stem. The seed capsule does not have hooks or burs.
Habitat: Rough-fruited Cinquefoil grows from a crown with fibrous roots. It is found in disturbed areas in full sun and tolerates soils that are heavier and more alkaline.
Names: The species name "recta" means "erect". The genus name, Potentilla, is from the Latin word potens, meaning 'powerful' and refers to the medicinal power of some species of the genus which have medicinally properties. The common name of 'rough-fruited' refers to the ridges on the seeds. 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. The other common names using 'sulfur' refer to the deep color of the petal base and 'five-fingers' is commonly used with the cinquefoils referring to the 5-lobed larger leaves that look like the five fingers of a hand.
Comparisons: Another non-native that is similar to this species is P. norvegica, the Rough Cinquefoil. But there all leaves are 3 parted and the flower sepals and bracts are longer than the petals.
Above: 1st photo - Example of a single flower cluster with one open. 2nd photo - The central receptacle is composed on numerous pistils and surrounded by 20 plus stamens.
Below: 1st photo - The inflorescence has a number of buds on short stalks with green bracts at the base. Sepals, bracts, stalks are all with white hair. 2nd photo - The triangular green hairy sepals (5) are much shorter than the petals and subtended by shorter, more lanceolate bracts.
Below: 1st photo - A mid-stem leaf. Note the hairy stipules at the stem. 2nd photo - A larger basal leaf with five leaflets.
Below: The seeds with their ridged surface. Photo ©Steve Hurst, USDA-NRCS Plants Database.
Notes: Rough-fruited Cinquefoil is an introduced plant, native to Europe and Asia. It is found in the entire United States except AZ, NM and UT; it is also found in all the lower Canadian Provinces. In Minnesota it is present in about 1/3 of the counties, mostly on the eastern half of the state. It is not considered invasive, but untended, it can form large clumps that are quite showy. Martha Crone listed 13 Cinquefoils on her 1951 Garden Census, this being one of them. There are 19 Cinquefoils that have been found in Minnesota of which 3 are introductions. Four of those have not been collected in many years and may not be extant.
Edwin Way Teale wrote: Many seeds already have fallen to the ground. Others have ridden away on parachutes of silk or have clung with the hooked hairs of their little burs to the fur or clothing of passersby. But many plants, like the rough-fruited cinquefoil, will continue to shake out their seeds, scattering them in the successive storms of winter. Compressed and dry, in varying shades and shapes, the tapestry of colors of next year’s flowers now lie waiting in the seeds. (from A Walk Through The Year, 1978)
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.
Friends of the Wild Flower Garden, Inc. Text and photos are by G. D. Bebeau unless otherwise credited. "www.friendsofthewildflowergarden.org"