There is a pith cavity on center of vascular bundle in O. minor, O. matsumuranus, O. marginatus and O. americanus.Some species have sclerotic cell or stone cell.

• 小叶月桂、牛矢果、厚边木犀、美洲木犀叶柄中央具髓腔，部分种叶柄有硬化细胞或石细胞存在。