A small genus of five species all endemic to China. They are small trees or shrubs with naked buds. Leaves are alternate with serrate or serrulate margins, stipules absent. Inflorescence usually a few-flowered pendulous raceme. Flowers hermaphrodite, corolla campanulate, divided almost to the base. There are eight to fourteen stamens all of equal length, ovary inferior. Fruit is a woody drupe, sometimes with conspicuous lenticels, containing a single seed (Hwang & Grimes 1996).
Sinojackia is little known and plays second fiddle in cultivation to the more familiar and showier Styrax and Halesia, but they have a quiet charm. The unusual generic name comes from sino meaning Chinese and ‘jackia’, which honours John George Jack (1861–1949) of the Arnold Arboretum. Jack, Canadian by birth, became Lecturer in Arboriculture in 1890 and used the arboretum’s living collections to teach students about trees and their botanical, economic and ornamental values. Jack also taught Chinese students who studied botany in the United States, including Hsen-Hsu Hu, who would go on to describe many of the Chinese Styraceae, later honouring Jack with the the genus Sinojackia. (Dirr 2009, Arboretum Foundation 1980).
Only two species, S. rehderiana and S. xylocarpa, are in general cultivation.
Pedicel to 2 cm. Fruit ellipsoid to narrowly ellipsoid with a long acuminate apical beak, 2–2.5 × 1–1.2 cm
Pedicel c. 3. cm Fruit ovoid with a conical apical beak or subglobose, 1.8–2 × 0.8–0.5 cm