4. Hosta shikokiana N. Fujita, Acta Phytotax. Geobot. 27: 93. 1976. Plants on Mt. Higashi-akaishi, Mt. Akaishi, Mt. Nishi-akaishi, and Mt. Shiragayama only.

Fig. 11

Type.

Japan. Ehime Pref., Mt. Higashi-akaishi, 7 Aug. 1957, T. Yamanaka 22475 (holotype KYO!) .

Phenology.

Flowering in July and fruiting in August.

Distribution and habitat.

Japan (Ehime and Kochi Prefectures) (endemic). This species grows in open habitats on the rocky ridgeline of Mt. Higashi-akaishi and its surrounding areas on Shikoku Island.

Conservation status.

Using criterion D1 for IUCN Red List categories (IUCN 2012, IUCN 2022), we recommend that this species be classified as VU (Vulnerable) because its population is estimated to be between 250 and 1000.

Japanese name.

Shikoku-giboshi (Fujita 1976).

Additional specimens examined.

Japan. Ehime Pref.: Mt. Higashi-akaishi, 15 Jul. 1952, T. Yamanaka 8901 with flowers (KYO!) ; ditto (as Mt. Akaishi), 9 Jul. 1928, G. Koidzumi s.n. with flower buds (KYO!) ; ditto, 1650 m elev., 21 Jun. 2021, T. Yahara et al. JPN6197, 6228, 6239, 6249, and 6252 with flower buds (FU!); ditto, 1640 m elev., 14 Jul. 1960, K. Tsuchiya 500 with flowers (KYO!); ditto, Mt. Hachimaki (a peak of Mts. Higashi-akaishi), 22 Jul. 2022, Se. Fujii JPN9953, 31 Jul. 2022, Se. Fujii JPN9954 with flowers (FU!); derived from Mt. Higashi-akaishi, cultivated in Makino Botanical Garden, 8 Apr. 2021, T. Yahara & Se. Fujii JPN3939-3942 sterile (FU!); between Mt. Higashiakaishi and Mt. Hutatsudake, 1600 m elev., 8 Sep. 1961, G. Murata 14981 with fruit (KYO!) ; ditto, cultivated stock of G. Murata 14981, G. Murata s.n. with flowers (KYO!). Kochi Pref.: Mt. Shiraga (cultivated stock), T. Yahara & Se. Fujii JPN3937, 8 Apr. 2021, sterile (FU!) ; ditto, Se. Fujii JPN9955, 23 Jul. 2021 with flowers (FU!) .

Note.

The following specimens cited by Fujita (1976) are not this species; the specimen from Mt. Kanpu (Yamawaki s.n., TI) is H. samukazemontana, and the specimens from Mt. Ishizuchi (Takahashi & Fujita 226, KYO; Takafuji s.n., KYO) are H. polyneuronoides .