わが国の本州、中部地方以北から北海道、それに千島列島やサハリン、朝鮮半島、中国に分布しています。山地の林内に生え、高さは6メートルほどになります。葉は広卵形で3中裂し、対生します。5月から7月ごろ、枝先に散房花序をだし、中心部に両性花、周囲に白い装飾花を咲かせます。装飾花はふつう5深裂して平開します。果実は核果で、秋に赤く熟します。ただこの果実は非常にまずく、食用には適しません。別名で「鳥食わず」と呼ばれることもあるそうです。中国語では「鶏樹条(ji shu tiao)」と呼ばれます。
韓国語では「ペクダンナム(백당나무)」です。語源の由来には諸説ありますが、京畿道の方言に由来するというのが有力です。それは白い花が咲くことと、葉の形がコウゾの葉に似ていることから、「白楮(ペクダク: 백닥나무 )」と呼ばれたものが「白当(ペクダン: 백당나무)」になったという説です。
スイカズラ科ガマズミ属の落葉低木で、学名は Viburnum opulus var. calvescens (syn. Viburnum opulus var. sargentii)。英名は Guelder rose。
The Guelder rose (Viburnum opulus var. calvescens) belongs to Caprifoliaceae (the Honeysuckle family). It is a small deciduous tree that is distributed northward from Chubu district of Hoshu to Hokkaido of Japan, as well as the Kuril Islands and Sakhalin. This tree grows in montane woodlands and can reach about 6 m in height. The leaves are broad ovate, trilobate and opposite. The corymbs are borne on the terminal branches and bloom white flowers. The bisexual flowers are at center and the neuter flowers are at around the periphery. The neuter flowers are usually five lobate and spread out. The fruits are drupes and ripen red in fall. However, this fruit tastes very bad and is not suitable for human consumption. I've heard it's sometimes called "Tori-kuwazu" (birds don't eat it). It is called "鶏樹条" (ji shu tiao) in Chinese.
In Korean, it's called "baek-dang-na-mu" (백당나무). While there are various theories regarding its etymology, the most widely accepted view is that it originates from a dialect of Gyeonggi Province. One theory suggests that a plant called "white kozo" (baek-dang-na-mu: 백닥나무), so named because it bears white flowers and its leaves resemble those of the kozo tree, eventually came to be known as "white dang" (baek-dang-na-mu: 백당나무).