Isodons are a diverse tribe of plants in the mint family (Lamiaceae). The unusual, multi-lobed shape of Isodon umbrosus var. hakusanensis leaves appears to be a defence mechanism. The complex shape deters the herbivorous weevil, Apoderus praecellens, from laying its eggs here by disrupting their leaf-processing behaviour.
See Higuchi, Y. & Kawakita, A.