This is a shapely deciduous shrub up to 6 ft or more high and more in width, of free and elegant growth, with grey, flaky bark; young shoots glabrous, yellowish. Leaves 11⁄2 to 31⁄2 in. long, nearly or quite as wide, roundish ovate in main outline, often heart-shaped at the base, usually three- sometimes five-lobed, the lobes doubly toothed; both surfaces are free from down, the lower one pale; stalk about one-third as long as the blade. Flowers white, 1⁄3 in. wide, opening in June, closely packed in rounded clusters 11⁄2 to 2 in. wide which come on short leafy twigs from the previous season’s growths, thus forming handsome sprays. Calyx with five-pointed ovate lobes; flower-stalks slender, 1⁄2 to 1 in. long; both densely covered with starry down.
Native of the mountains of Colorado, at altitudes of 5,000 to 6,000 ft. It was introduced in 1904 under the specific name of “Ramaleyi”, but subsequently seems to have disappeared. It was reintroduced in 1930. It is most nearly akin to P. malvaceus and P. monogynus, having, like them, only two carpels to each fruit which are united half their length, whereas in the common P. opulifolius there are three to five carpels united only at the base. It differs from them in the obovate or spatulate floral bracts being more persistent.