Hovenia is a small genus of deciduous trees and shrubs belonging to the family Rhamnaceae, within the order Rosales. The genus comprises a handful of species native to a broad arc of temperate and subtropical Asia, stretching from India eastward through China to Japan and Korea.
The most widely known member is Hovenia dulcis Thunb., commonly called the Japanese raisin tree or Oriental raisin tree. It is noteworthy for its fleshy, sweet, edible peduncles — the thickened, branched flower stalks that develop after fruiting and are consumed as a food and traditional remedy across East Asia. The tree is frequently planted as an ornamental and shade tree outside its native range.
Hovenia acerba is another recognised species within the genus. The wider genus also includes Hovenia parviflora, Hovenia pubescens, Hovenia robusta, Hovenia tomentella, and Hovenia trichocarpa, though the exact species boundaries have been revised over time.
The fossil record extends the genus back at least to the Oligocene in Japan (Hovenia palaeodulcis), and fossil wood resembling Hovenia has been described from the late Eocene Florissant Fossil Beds of Colorado, representing the earliest known occurrence of this otherwise Asian genus in North America.
Etymology
The genus name Hovenia honours David ten Hove, an eighteenth-century Dutch senator and patron of the natural sciences, to whom the Swedish botanist Carl Peter Thunberg dedicated the genus when describing Hovenia dulcis in 1781.
Distribution
Hovenia is native to a range spanning from northern India through China, Korea, and Japan. The most cultivated species, Hovenia dulcis, is widely planted as an ornamental outside this native range, including in parts of Europe and the Americas.
History
Fossil wood resembling Hovenia has been recovered from the late Eocene Florissant Fossil Beds National Monument in Colorado, USA — the first record of this otherwise Asian genus in North America — alongside an Oligocene species, Hovenia palaeodulcis, from Japan, indicating a much wider prehistoric distribution than the genus holds today.
Cultural Uses
Hovenia dulcis, the Japanese raisin tree, has long been used across East Asia. The swollen, fleshy peduncles that develop after flowering are eaten fresh or dried and have a sweet, raisin-like flavour. The species is also used in traditional medicine in China, Japan, and Korea, where extracts are employed to treat alcohol intoxication and liver complaints.
