わが国の北海道西南部から九州それに中国に分布しています。山地の渓流沿いに生え、高さは30メートルほどになります。葉は長い柄のある大形の掌状複葉です。4月から5月ごろ、枝先に直立した円錐花序をつけ、やや紅色を帯びた花をいっぱいに咲かせます。花はミツバチの蜜源となりますが、このトチ蜜はやや苦みがあるそうです。また果実は、渋抜きをしてトチ餅に利用されます。中国語では「日本七葉樹(ri ben qi ye shu)」と呼ばれます。
トチノキ科トチノキ属の落葉高木で、学名は Aesculus turbinata。英名は Japanese horse chestnut。
The Japanese horse chestnut (Aesculus turbinata) belongs to Hippocastanaceae (the Horse-chestnut family). It is a tall deciduous tree that is distributed southward from southwestern Hokkaido to Honshu, Shikoku, and Kyushu in Japan, as well as China. This tree grows along mountain streams and can reach about 30 m in height. The leaves are large and palmately compound with long petioles. The erect panicles are borne on the terminal branches and produce rose-pink flowers from April to May. They are nectar-bearing flowers and attract bees, though the honey has bitter taste. The fruit is used in "Tochi-mochi" (Japanese horse chestnut cake) after the astringency is removed. (edit by Greg Brockelbank) In Chinese, it is called "日本七葉樹" (ri ben qi ye shu).