Sciaphila secundiflora Thwaites ex Benth., Hooker’s J. Bot. Kew Gard. Misc. 7: 10, 1855.

Sciaphila tosaensis Makino, Bot. Mag. (Tokyo) 19: 140, 1905. TYPE: Japan. Shikoku. Kochi Pref. Prov. Tosa, Jul. 1906, Y. Tokihisa 24941 (neotype, MAK, designated by Ohashi et al., J. Jap. Bot. 83: 28, 2008); Seychellaria tosaensis (Makino) T. Itô, Bot. Mag. (Tokyo) 21: 85, 1907; Parexuris tosaensis (Makino) Nakai & Maek., Iconogr. Pl. Asiae Orient. 1: 23, 1936.

Sciaphila boninensis Tuyama, Bot. Mag. (Tokyo) 50: 425, 1936. Sciaphila megastyla Fukuy. & T. Suzuki, J. Jap. Bot. 12: 412, 1936; Sciaphila tosaensis var. megastyla (Fukuy. & T. Suzuki) S. S. Ying., Mem. Coll. Agric. Natl. Taiwan Univ. 29: 89, 1989.

Korean name: Gin-Yeong-Ju-Pul (긴영주풀) 국명신칭

Plants saprophytic herb, white, pink or brownish to reddish purple; roots with filiform lateral branches. Stems appearing usually from July to September, simple, sometimes branched at base, erect, with a few alternate scaly leaves; 2–8(−20) cm long, 0.2–0.7 mm in diameter. Leaves ovate or narrowly ovate, acuminate, 2–3.5 mm long. Inflorescences terminal racemose, erect, with 1–4(−35) flowers, male flowers towards apex, female flowers toward base; bracts narrowly ovate, scale-like, 1–4 mm long; pedicels 1–5 mm long. Male flowers 6–7mm across; perianth 4–8, usually 6, connate at base, equal, narrowto linear-triangular, 2–5 × 0.2–0.5 mm, apex glabrous, without appendages; stamens usually 3, subsessile. Female flowers 3–4(− 5)mm across; perianth 4–10, segments equal, apex glabrous; pistils 10–80, free; ovary obovate, 0.5–1mm long, apex rounded, densely glabrous; papillate; style clavate, inserted laterally at base, exceeding ovary; stigma with dense cylindrical papillae. Fruit achene, ca. 3.5 mm in diameter, obovoid, longitudinally lined, apex densely minute processes. Seed 1, ellipsoidal, 0.5–1 mm long, surface reticulate.

Distribution: Korea, Jeju; Japan, Honshu (Nigata, Tokyo, Shizuoka, Mie, Wakayama, Kyoto, Hyogo, and Hiroshima Prefectures), Shikoku, Kyushu and the Ryukyus (Okinawa and Iriomote-jima islands); Taiwan, Kueishan and Lanyu islands; Hong Kong; Thailand; Sri Lanka; Malaysia; New Guinea; Solomon Islands

Habitat: Evergreen broad-leaved forest dominated by Quercus acuta Thunb. and Castanopsis sieboldii (Makino) Hatus. ex T. Yamaz. & Mashiba; co-occurred with mycoheterotrophic plants, Burmannia championii Thwaites, B. cryptopetala Makino, and Monotropa hypopithys L.; moist humus-rich soil; south-eastern face of Mt. Hallasan on Jeju Island, ca. 290 m above sea level; the number of individuals was very small as ca. 30. (Fig. 1)

Specimens examined: KOREA. Jeju Special Self-Governing Province: Seogwipo-si, Namwon-eup, Hannam-ri, 26 Jul 2016, Kim J. and C. U. Kim 63761 (WTFRC); Seogwipo-si, Namwon-eup, Hannam-ri, 13 Jul 2017, Yim E. Y. et al. 64478 (WTFRC).

Sciaphila secundiflora is easily distinguished from S. nana by the size and shape of male flower. We chose the Korean name ‘Gin-Yeong-Ju-Pul’ because this species has the longer perianths than Yeong-Ju-Pul (S. nana) and ‘Gin’ means long in Korean.

Notes: It is known that S. secundiflora is distributed in Japan, Taiwan, Hong Kong, Thailand, Sri Lanka, Malaysia, New Guinea, and Solomon Islands. Moreover, this study presents that this species was discovered in Korea. In addition, S. nana is distributed in Korea, Japan, Thailand, Vietnam, Philippines, Malaysia, and Indonesia. The distribution of these species ranges from warm to tropical regions. The occurrence of the tropical and subtropical plants can be affected by ecosystem changes due to climate change. The world’s northernmost limit of S. secundiflora is Nigata Prefecture, Japan, and of S. nana is Miyagi Prefecture, Japan (Ohashi et al., 2008). Presence of these taxa in Korea, which is located between Japan and other area, is phytogeographically and climatically significant.

Sciaphila secundiflora and S. nana occurred on the moist humus-rich soil in dense forests of Jeju and inhabit with the mycoheterotrophic plants, Burmannia championii Thwaites and B. cryptopetala Makino. These plants and those habitats are very rare, small, and only appear above ground when they are in flower or fruit. Therefore, the number of collections is very small, and accurate information on distribution is limited.

The plants of Sciaphila are vulnerable species to the change in environment condition (Uchida et al., 2012), and are designated as the vulnerable species or endangered species in the Red List of vascular plants in China, Japan and Taiwan. However, the criteria for conservation of these taxa and their habitats are not yet established in Korea.

We therefore suggest that further continuous monitoring on the genus Sciaphila in Korea is needed for evaluation as climate change indicator species and rare species. In addition, we think that the presence of S. secundiflora and S. nana in Korea is important for its phytogeographic and climatic significance and propose that these species should be protected at the vulnerable species level for the habitat characteristics.