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This species, which occurs over a wide area of North America east of the Rocky Mountains is so closely allied to the Old World S. racemosa that some authorities do not separate them. The American shrub is distinguished by its young shoots, leaves and flower-stalks being downy, the brown pith, and the fruit-panicles not so densely packed with berries.
S. pubens var. leucocarpa Tott. & Gr
S. racemosa f. xanthocarpa Cockerell