わが国の各地をはじめ、アジアからヨーロッパ北・西部、北アメリカに広く分布しています。海岸の砂地に生え、地面を這って長さは1メートルほどになります。茎は角ばり、葉は小葉が6〜12個ある複葉です。4月から7月ごろ、総状に蝶形花を咲かせます。旗弁は初め赤紫色ですが、あとで青紫色に変わります。まれに白花もあるそうです。中国語では「海濱山黧豆(hai bin shan li dou)」と呼ばれます。
The Beach pea (Lathyrus japonicus) belongs to Fabaceae (the Pea family). It is a perennial herb that is distributed widely, throughout Japan, Asia, northern and western Europe and North America. This herb grows on coastal sandy soils, spreads by creeping on the grounds and can reach about 1 m long. The stem is angulate and the leaves are compound with 6-12 leaflets. The racemes are borne on the stalks and the papilionaceous flowers bloom from April to July. The vexillum is magenta at beginning and turns bluish-purple gradually. The flower-color is rarely white. It is called "海濱山黧豆" (hai bin shan li dou) in Chinese.