The "Tama-ajisai" (Hydrangea involucrata) belongs to Hydrangeaceae (the Hydrangea family). It is a small deciduous tree that is native southward from southern Tohoku district of Honshu to Shikoku, Kyushu of Japan. This tree grows along mountain streams and can reach 1.5-2 m in height. It is much branched and the leaves are elliptic to ovate-elliptic with fine toothed edges. The compound corymbs are borne on the new branches and bloom pale purple bisexual flowers at center, neuter white flowers at around the periphery from August to September. The buds are round and covered with bracts.