The formation of periderm is relatively late and cork cambium is come from the cortex cells which arenear endodermis.
周皮发生较迟，其木栓形成层由紧靠内皮层的皮层细胞产生。
2
Externally pale brownish-yellow or pale brown, with irregular, longitudinal wrinkles, cork easily exfoliated, exposing yellowish-white cortex, sometimes showing reticulated fibre bundles.