An elegant, pendulous-branched shrub up to 10 ft high, the young shoots glabrous, the year-old bark peeling. Leaves three-nerved, ovate, 11⁄2 to 3 in. long, 3⁄4 to 2 in. wide, shortly and broadly toothed, or nearly entire (especially on the flowering twigs), either glabrous or slightly downy beneath. Flowers 1 in. or less wide, pure white, slightly fragrant, produced numerously in panicles at the end of the shoot, often over twenty flowers in each. Petals oblong-obovate; calyx glabrous outside the lobes, downy on the margins, and near the apex inside; styles united, stigmas separated.
Native of California. Although much confused with P. lewisii, and sometimes regarded as a variety of it, this is really one of the most distinct of American species. On weak shoots its inflorescence may be only a simple raceme, but normally it is composed of several racemes, thus forming a true panicle. Flowers small and crowded. The base of the leaf-stalk does not hide the axillary bud, as it does in P. lewisii.