Lasianthus sikkimensis Hook.f. (1880: 180)

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

63. Lasianthus sikkimensis Hook.f. (1880: 180) — Fig. 93 (plate), Fig. 94 (map)

Type: — INDIA. Sikkim, Hooker & Thomson 11 (holotype K! [K000031598]; isotypes L! [L0000706, L0000705], LE! [ LE00017554 ]) .

Lasianthus tsangii Merr. ex H.L.Li (1943: 457) . Type:— CHINA. Kwangsi (Guangxi), W.T.Tsang 23940 (holotype IBSC!).

Lasianthus baviensis (Drake) Pit. (1924: 380) . Type:— VIETNAM. Ha Noi City, Ba Vi District , 1 July 1887, Balansa 2655 (holotype P! [P04009933]; isotype K! [K000777006]).

Lasianthus langkokensis (Drake) Pit. (1924: 397) . Type:— VIETNAM. Ha Noi City, Ba Vi District , 1 October 1887, Balansa 2654 (holotype P!).

Specimens examined: — VIETNAM. Northern: Vinh Phuc Province, Tam Dao National Park, 1124 m elev., 13 November 2018, Dang V.S. & Naiki A., Dang 237 ( VNM, the herbarium of Iriomote Station (Japan)); Ha Noi City, Ba Vi National Park , 1267 m elev., 17 November 2018, Dang V.S. & Naiki A., Dang 281 ( VNM, the herbarium of Iriomote Station (Japan )) .

Distribution: —Widespread in the tropical and subtropical regions in Asia ( Bangladesh, China, India, Malaysia, Philippines, Thailand). In Vietnam, Lasianthus sikkimensis occurs in Ha Noi, Hoa Binh, and Vinh Phuc.

Habitat & Ecology: —Growing in the shade of evergreen forest or the hill of evergreen montane forest at 700– 1300 m elev.

Phenology: —Flowering and fruiting from July to November.

Vernacular name: —Xú hưƠng ba vì, Xú hưƠng lăng cốc.

Notes: — Lasianthus sikkimensis was described in 1880 by Hooker. It was clarified in the revision by Zhu et al. (2012) and two Vietnamese species, L. langkokensis (Drake) Pit. (1924: 397) and L. baviensis (Drake) Pit. (1924: 380) were treated as the synonyms of L. sikkimensis .

This species is easily identified in the field by having densely brown-tomentose on branches, leaf blade ellipticlanceolate or elliptic, 10–20 cm long, bracts linear to lanceolate, 0.5–2 cm long, brown-tomentose, and fruits ellipsoid, blue when ripe.

Figures

FIGURE 93. Lasianthus sikkimensis Hook.f. (from Dang 281, VNM and the herbarium of Iriomote Station (Japan)): A. Habit, B. Branch, C. Stipules, D. Abaxial leaf surfaces, E–G. Inflorescence showing side view bracts, buds and flowers, H. Young fruits, I–J. Mature fruits.

FIGURE 94. Distribution maps of Lasianthus sikkimensis, L. sonlangensis, L. stephanocalycinus and L. tamdaoensis.