Synonyms: Potentilla leucocarpa, Potentilla millegrana, Potentilla millegrana var. millegrana, Potentilla pentandra, Potentilla rivalis var. millegrana, Potentilla rivalis var. pentandra, Potentilla rivalis var. rivalis, Tridophyllum rivale
The photo above shows brook cinquefoil as seen in sandy soils along the Columbia River at The Dalles, OR.......August 26, 2001.
Sometimes known as stream-bank cinquefoil, brook cinquefoil is an annual to biennial wildflower with a spreading to erect growth form. The stems are often stout and simple to branched from the base, and 20-60 cm long. The herbage is often tomentose and glandular. The basal and lower stem leaves are long-petioled. The lower leaves often have 5 leaflets or only 3 leaflets with the terminal one in turn deeply 3-cleft or parted. The blades are 3-5 cm long, oblanceolate to obovate in shape with coarse, irregular teeth on the margins.
The inflorescence is often leafy and flower bearing much of the length of the stem. The five calyx lobes are 4-5 mm long and the 5 petals are a light yellow, ranging from one-half to almost the same length as the calyx (See photo above.) Individual petals are obovate or oblanceolate with rounded to blunt tips. The stamens number either 10 or 15.
Brook cinquefoil may be found along the margins of lakes, ponds, rivers and streams and in swamps.
Brook cinquefoil may be found from British Columbia south along the east side of the cascade Mts. in British Columbia, Washington, and Oregon. It extends west down the Columbia River Gorge then south throught the Willamette Valley to southwestern Oregon and south along the coast in California. Its range estends eastward to Saskatchewan, minnesota, Illinois, Missouri, New Mexico and northern Mexico.
The photo above shows the leaf of brook cinquefoil along the Columbia River at The Dalles, OR.......August 26, 2001.