Lasianthus nhatrangensis V.S.Dang & Naiki (2021: 16)

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

52. Lasianthus nhatrangensis V.S.Dang & Naiki (2021: 16) — Fig. 80 (plate), Fig. 78 (map)

Type: — VIETNAM. Khanh Hoa Province, Hon Ba Nature Reserve, 400 m elev., 13 July 2014, Tagane S., Kanemitsu H., Dang V.S., Tran H. with Hanh N., Loi X.N., Thach N.D., Dinh N., Hieu P.N.H. V 1563 (holotype VNM! [ VNM00042923 ]; isotypes FU!, VNM! [ VNM00042924 , VNM00042925 ], the herbarium of Iriomote Station (Japan)) .

Specimens examined: — VIETNAM. Central: Khanh Hoa Province, Hon Ba Nature Reserve, 400 m elev., 12°06’31.02’’N, 108°59’14.01’’E, in evergreen forests, 13 July 2014, Tagane S., Kanemitsu H., Dang V.S., Tran H. with Hanh N., Loi X.N., Thach N.D., Dinh N., Hieu P.N.H. V 1563 ( 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: —Low montane forest under the shade of the canopy at ca. 400 m elev.

Phenology: —Flowering and fruiting from March to July.

Vernacular name: —Xú hưƠng nha trang.

Notes: — Lasianthus nhatrangensis is similar to L. bokoensis Naiki (2015: 156) which was recently discovered from Bokor National Park, Cambodia, in the shade of the leaves and fruits, number of pyrenes, but differs in having shorter petioles (3–5 mm long vs. 6–9 mm long), smaller stipules (1.5–2 mm long vs. 2–3 mm long) and calyx (1–1.5 mm long vs. 1.7–2 mm long for tubes and 2–3 mm long vs. 3–4.5 mm long for lobes).

Figures

FIGURE 78. Distribution maps of Lasianthus nghiasonii, L. nhatrangensis, L. ngoclinhensis, L. nuichuaensis and L. oblongilobus.

FIGURE 80. Lasianthus nhatrangensis V.S.Dang & Naiki (from V1563, VNM): A. Branch with young fruits, B. Close-up of expanding young leaves, C. Stipules, D. Abaxial leaf surfaces, E. Inflorescence showing side view flower buds, F–G. Fruits, J. Seeds (G: photos by Shuichiro Tagane).