The "Inu-kori-yanagi" (Salix integra) belongs to Salicaceae (the Willow family). It is a small deciduous tree that is native to Japan and the southern Kuril Islands. This tree grows in sunny marshes or stream banks and it can reach 2-3 m in height. The leaves are elliptic, about 5 cm long and opposite with dull points. It is dioecious. The short catkins are borne from March to May before foliation. The seeds are covered with woolly hairs.