Calycanthus occidentalis, commonly called spice bush or western sweetshrub, is a species of flowering shrub in the family Calycanthaceae that is native to California and, according to some sources, Washington state. It grows along streams and moist canyons in the foothills of mountains. Calycanthus occidentalis is a deciduous shrub that can reach a height of 4 m (13 ft). Its leaves are opposite, and grow to about 5–15 cm (2–6 in) long and 2–8 cm (0.8–3.1 in) wide. They are more-or-less ovate with acute tips, a rounded base. The flowers appear from late spring to early fall. The flowers do not have distinctive sepals and petals, but have swirls of dark red to burgundy colored petal-like structures called tepals, 2–6 cm (0.8–2.4 in) long and 0.5–1 cm (0.2–0.4 in) wide. The flowers open to about 5 cm (2 in) wide. The tepals enclose about 10–15 stamens. The flowers are pollinated by beetles of the family Nitidulidae. Calycanthus occidentalis is native to California and, according to some sources, Washington. It grows along streams and on moist canyon slopes at elevations of 200–1,600 m (700–5,200 ft). Calycanthus, called sweetshrub, is a genus of flowering plants in the family Calycanthaceae. The genus includes two to four species depending on taxonomic interpretation; three are accepted by most 21st century sources.