オトギリソウ科オトギリソウ属の多年草で、学名は Hypericum kamtschaticum var. hondoense。英名はありません。
"Iwa-otogiri" (Hypericum kamtschaticum var. hondoense) belongs to the family Clusiaceae. It is a perennial herb that is distributed to northward from Chubu district to the Japan Sea side of Honshu and Hokkaido in Japan. This herb grows in sub-alpine to alpine grasslands or screes and can reach 10-20 cm in height. The leaves are elliptic, opposite and scatter many black dots and a few bright dots on the surface. The yellow flowers bloom in July to August. It is a variant of "Shinano-otogiri", characterized by slightly smaller flowers and more black spots on the inner side of the sepals than on the margins.