Flowers campanulate and rusty white faintly checkered with rusty peach colour; shoulders usually patterned with dark brown lines or dots. Tepals similar to or slightly narrower than those of F. koidzumiana, but entire or only obscurely toothed or fimbriate. Nectaries located 1/4 from the base of the tepals. Anthers rusty white.
The specific epithet and vernacular name refer to Kai (present-day Yamanashi Prefecture) where this species was found.
In Yamanashi, Shizuoka and Tokyo Prefectures.