Pterostyrax, commonly known as the epaulette tree, is a small genus of four species of deciduous large shrubs or small trees belonging to the family Styracaceae, within the order Ericales. The genus is native to eastern Asia, with species distributed across China and Japan.
Plants in this genus typically grow 4–12 metres (13–39 ft) tall. The leaves are alternate, simple, and ovate, measuring 6–17 cm long and 4–10 cm broad. The flowers are white and produced in showy, dense panicles 8–25 cm long, giving rise to the common name "epaulette tree" due to the pendant flower clusters resembling military epaulettes.
The fruit is an oblong dry drupe distinguished by prominent longitudinal ribs or narrow wings. It is this winged fruit that sets Pterostyrax apart from the closely related genus Styrax, whose fruits lack wings — a distinction encoded in the genus name itself (Greek pteron, wing + Styrax).
The genus comprises four species: P. hispidus (Japan), P. corymbosus (Japan and China), P. psilophyllus (China), and P. burmanicus. Species names are frequently given with feminine gender (e.g., corymbosa), but the genus is correctly masculine in gender.
Etymology
The name Pterostyrax combines the Greek word pteron (wing) with Styrax, the related genus, meaning "winged styrax." This refers to the distinctive longitudinal wings or ribs on the fruit of Pterostyrax species, which are absent in Styrax.
Distribution
Pterostyrax is native to eastern Asia, with species occurring in China and Japan. P. hispidus is found in Japan; P. corymbosus occurs in both Japan and China; P. psilophyllus is native to China.
