Lasianthus khanhhoaensis V.S.Dang & Naiki (2021: 18)

Dang, Van-Son & Naiki, Akiyo, 2023, A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam, Phytotaxa 581 (1), pp. 1921-1935 : 1921-1935

36. Lasianthus khanhhoaensis V.S.Dang & Naiki (2021: 18) — Fig. 60 (plate), Fig. 57 (map)

Type: — VIETNAM. Khanh Hoa Province, Hon Ba Nature Reserve, 617 m elev., 22 November 2014, Toyama H., Tagane S., Dang V.S., Nagamasu H., Naiki A., Tran H., Yang C.J. with Cuong N.Q., Hieu H.N.P. V1967 (holotype VNM! [ VNM00042901 ]; isotypes FU!, VNM! [ VNM00042902 , VNM00042903 ], the herbarium of Iriomote Station (Japan)) .

Specimens examined: — VIETNAM. Central: Khanh Hoa Province, Hon Ba Nature Reserve, 617 m elevation, 12°06’39.77’’N, 108°58’59.23’’E,in evergreen forests, 22 November 2014, Toyama H., Tagane S., Dang V.S., Nagamasu H., Naiki A., Tran H., Yang C.J. with Cuong N.Q., Hieu H.N.P. V1967 ( FU, VNM, the herbarium of Iriomote Station (Japan)); in the same location, 617 m elev., 12°06’39.07’’N, 108°58’59.23’’E, in evergreen forests, 21 February 2014, Toyama H., Dang V.S., Tagane S., Fuse K., Yahara T., Nagamasu H., Tran H. with Ngoc N.V., Cuong N.Q., Thach N.D., Hieu H.N.P. V 1187 ( FU, VNM, the herbarium of Iriomote Station (Japan )) .

Distribution: —Endemic to Vietnam (known only from the Hon Ba Nature Reserve, Khanh Hoa Province).

Habitat & Ecology: —In hill evergreen forest at 600–700 m elev.

Phenology: —Flowering and fruiting from February to November.

Vernacular name: —Xú hưƠng khánh hòa.

Notes: — Lasianthus khanhhoaensis is similar to L. stephanocalycinus Naiki, Tagane & Yahara (2015: 173) which was recently discovered in Bokor National Park, Cambodia, in the shape of leaves, inflorescences, and fruit color, but differs from the latter in having larger leaves (12–14 × 2.5–3.5 cm vs. 8–9.5 × 3–3.5 cm), shorter stipules (1–2 mm long vs. 2–3 mm long) and smaller calyx lobes (1.5–2.5 mm long vs. 2.5–3 mm long).

It is also similar to L. bachmaensis V.S.Dang & Naiki which was described from Bach Ma National Park, Central Vietnam, but differs from the latter in having plants covered by densely villous (vs. sparsely pubescent or subglabrous), larger leaves (12–14 × 2.5–3.5 cm vs. 10–12 × 2–2.5 cm) and smaller calyx tubes (1.5–2 mm long vs. 1–1.5 mm long).

Figures

FIGURE 57. Distribution maps of Lasianthus inodorus, L. japonicus, L. kbangensis and L. khanhhoaensis.

FIGURE 60. Lasianthus khanhhoaensis V.S.Dang & Naiki (from V1967, VNM): A. Branch with fruits, B. Close-up of young branch and leaves, C. Stipules, D. Abaxial leaf surfaces, E–G. Inflorescence showing side view calyxes and flower, H–I. Fruits, J. Seeds (F–G: photos by Shuichiro Tagane).