​Japan (Bonin Islands, Shikoku [Okinoshima Isl., Sukumo-shi, Kochi Pref.], Kyushu [Nagasaki Pref. and Kagoshima Pref.], Ryukyu [throughout, excluding Amami-oshima isl., Ishigaki Isl. and Iriomote Isl.; Fig. 5) and Taiwan (Lanyu Isl.).

​Basé sur C. falcatum (L.f.) C.Presl subsp. australe S.Matsumoto, nom. nud., Ann. Tsukuba Bot. Gard. 22: 70, 2003.

​Typus: JAPAN. Tokyo Pref, Bonin Islands., Ogasawara-mura, Isl. Chichijima, northern part of Mt. Mikazukiyama, alt. 74 m (R. Hirayama s.n., originally collected on Jan. 29, 1981, specimen collected from a cultivated stock in Tsukuba Botanical Garden (stock No. 13613) on May 14, 1988, holo-TNS [VS-1268928]).