Five-Finger Cinquefoil, Rough-Fruited Cinquefoil, Tall Five-Finger, Tormentil, Upright Cinquefoil, and Yellow Cinquefoil.
Sulfur Cinquefoil is a perennial forb with a single, woody taproot that can grow from one to three feet in height. This plant may have spreading roots, but they are not rhyzominous. The rosette of this plant has long-petiolate leaves which whither before flowering. Leaves are palmate with five to seven toothed leaflets that radiate from the center point. Leaves are approximately two to four inches long and up to an inch wide and resemble marijuana leaves. Leaves are more numerous at the base. Each rosette will produce a stem which remains unbranched until the cluster of flowers. Flowering occurs from May through July and flowers have five light yellow petals with deeply notched tips and a darker yellow center. Seeds are comma shaped, dark brown, have net-like ridges, and narrow winged edges. Sulfur cinquefoil can be spread through seed and by root.
The key features of this plant include pointed hairs which protrude outward at right angles from the stem and leafstalk. Leaves of sulfur cinquefoil have green coloring rather than silver on the underside of the leaf.
Sulfur cinquefoil prefers full sunlight and has adapted to a wide range of soil conditions. It can commonly be found in grasslands, shrubby/forested areas, logged areas, roadsides and waste areas.
Currently found in the following counties:
Beaverhead, Big Horn, Broadwater, Carbon, Cascade, Chouteau, Flathead, Gallatin, Granite, Hill, Judith Basin, Lake, Lewis & Clark, Lincoln, Madison, Meagher, Mineral, Missoula, Park, Powell, Ravalli, Rosebud, Sanders, Stillwater, Teton, Wheatland, Yellowstone.
Three obvious characteristics distinguish sulfur cinquefoil from native cinquefoils: Leaves of sulfur cinquefoil appear green on the underside rather than silvery; sulfur cinquefoil seeds are ridged while other cinquefoil seeds usually are not; and sulfur cinquefoil has comparatively more stem leaves and fewer basal leaves than other Potentilla species. The fruit of sulfur cinquefoil is edible, and the plant was used by Indians to treat wounds as it causes tissues to contract.
Commonly Confused Plants:
There are three native Potentilla species in Montana with five-leaflet palmately compound leaves that could be confused with sulfur cinquefoil. Potentilla quinquefolia is reported from alpine and subalpine areas in Flathead, Glacier, Granite, Madison, and Park Counties and is small, only reaching 8 inches (20 cm) tall, has three leaflets on the basal leaves, the lower surface having grey, tangled, wooly hairs (lanate). Potentilla diversifolia, found in alpine areas in west and central Montana, has mainly basal leaves with few leaves along the stem, the flowers have only 20 stamens, the plant is not hirsute-hispid, and the achene surface is smooth. Sulfur cinquefoil is most often confused with northwest cinquefoil, Potentilla gracilis, found in most of Montana’s counties. Northwest cinquefoil is variable in its morphological characteristics. It generally has fewer leaves along the stem than sulfur cinquefoil, the leaves can, but not always, have white wooly hairs on the lower (ventral) surface, or some plants are fuzzy with short hairs (pubescent) or appearing without hairs (but never hirsute-hispid), and the achenes are smooth. Because of the leaves, sulfur cinquefoil has been confused with hemp, Cannabis sativa. However, hemp plants are hairless annuals commonly growing to well over two feet tall, and the flowers are small, green, and dioecious.
Photo Credits: Matt Lavin; Joseph M. DiTomaso, University of California - Davis, Bugwood.org