[Wikipedia] Description, Taxonomy, Ecology, Uses: Taxonomy There are two varieties, not considered distinct by all authorities: Cephalanthus occidentalis var. occidentalis (syn. var. pubescens) common buttonbush. Eastern North America from Nova Scotia west to Minnesota and south to Florida and east Texas. Cephalanthus occidentalis var. californicus California button-willow. Southwestern North America, from west Texas west to California (Sierra Nevada foothills, San Joaquin Valley, Sacramento Valley, and the Inner North Coast Ranges) and south to Mexico and Central America. Ecology Waterfowl and other birds eat the seeds. Wood ducks utilize the plant as nest protection, and mallards eat the fruit.[6] Deer browse the foliage, which is poisonous to livestock.[7] Insects and hummingbirds take the nectar, with bees using it to make honey.[5][8] It is a larval host to the hydrangea sphinx, the royal walnut moth, and the titan sphinx.[9] Uses Medicinal Cephalanthus occidentalis has a number of historical medicinal uses, but it is also toxic due to the presence of cephalanthin.[5][8] (link added by Mary Ann Machi)