Cephalanthus occidentalis is a species of flowering plant in the family Rubiaceae that is native to eastern and southern North America. Common names include buttonbush, common buttonbush, button-willow, buck brush, and honey-bells.
Description
Cephalanthus occidentalis is a deciduousshrub or small tree that averages 1–3 m (3.3–9.8 ft) in height, but can reach 6 m (20 ft). The leaves are opposite or in whorls of three, elliptic to ovate, 7–18 cm (2.8–7.1 in) long and 4–10 cm (1.6–3.9 in) broad, with a smooth edge and a short petiole. The flowers are arranged in a dense spherical inflorescence 2–3.5 cm (0.79–1.38 in) in diameter on a short peduncle. Each flower has a fused white to pale yellow four-lobed corolla forming a long slender tube connecting to the sepals. The stigma protrudes slightly from the corolla. The fruit is a spherical cluster of achenes (nutlets).[4]
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.
The species occurs in eastern North America with disjunct populations occurring in the west. In Canada, it occurs from southern Ontario and Quebec east to New Brunswick and south-western Nova Scotia. Besides the eastern United States, and eastern regions of the Midwest, notable areas range into Arizona, the Mogollon Rim, and other mountain ranges; in California, the entire San Joaquin Valley[10] West of the Great Plains and the Rocky Mountains, only western Texas, Arizona, and California find C. occidentalis.
Uses
Medicinal
Cephalanthus occidentalis has a number of historical medicinal uses, but it is also toxic due to the presence of cephalanthin.[5][8]
Cultivation
Buttonbush is cultivated as an ornamental plant for a nectar source or 'honey plant' and for aesthetics in gardens and native plant landscapes, and is planted on slopes to help control erosion.[11] Buttonbush is a suitable shrub for butterfly gardens.
The town of Buttonwillow, California was named for the buttonbush (Cephalanthus occidentalis). A lone buttonbush served as a landmark on an old trans-San Joaquin Valley trail, and was used by ancient Yokuts as a meeting place. It later became the site of settlers' stock rodeos. This buttonbush tree is listed as California Historical Landmark No. 492, and is now known as the "Buttonwillow Tree".[12]
^"Cephalanthus occidentalis"(PDF). Digital Representations of Tree Species Range Maps from "Atlas of United States Trees" by Elbert L. Little, Jr. (and other publications). United States Geological Survey.
^"Cephalanthus occidentalis L. buttonbush"(PDF). Wildland Shrubs of the United States and its Territories: Thamnic Descriptions. United States Forest Service. Archived from the original(PDF) on 26 March 2009. Retrieved 2009-09-14.
^Niering, William A.; Olmstead, Nancy C. (1985) [1979]. The Audubon Society Field Guide to North American Wildflowers, Eastern Region. Knopf. p. 764. ISBN0-394-50432-1.
^Little, Elbert L. (1980). The Audubon Society Field Guide to North American Trees: Eastern Region. New York: Knopf. p. 667. ISBN0-394-50760-6.
