Sinojackia is a small genus of deciduous shrubs and small trees in the family Styracaceae (storax family), placed within the order Ericales. The genus comprises five to eight accepted species, all of which are endemic to China, making it one of the more geographically restricted genera in the family.
Members of the genus typically grow to between 4 and 12 metres in height. As deciduous plants, they shed their leaves seasonally, a trait shared with many other members of the Styracaceae. The family Styracaceae is best known for ornamental and commercially notable relatives such as the snowbell genus Styrax and Halesia (silverbell trees).
The genus includes several species of conservation concern. Sinojackia sarcocarpa is critically rare: as of a 2017 report by botanist Mikinori Ogisu at Chiba University, fewer than 20 individuals were known to exist in the wild, placing it among the most endangered woody plants in China. Other species in the genus, including Sinojackia xylocarpa and Sinojackia rehderiana, have been cultivated in botanical gardens outside China and are occasionally grown as ornamental specimens in temperate gardens.
Distribution
All species of Sinojackia are endemic to China. The genus has no native range outside of Chinese territory, making it one of the strictly China-restricted genera within the Styracaceae.
Conservation
At least one species, Sinojackia sarcocarpa, is critically endangered in the wild. Botanist Mikinori Ogisu reported in 2017 that fewer than 20 individuals of S. sarcocarpa were known to remain in their natural habitat. Several species are maintained in cultivation at botanical gardens, which may represent an important ex situ conservation resource.
