Lasianthus verticillatus Merr. 1935

70. Lasianthus verticillatus (Lour.) Merr. (1935: 372) — Fig. 102 (plate), Fig. 99 (map) Type: — VIETNAM. G. Dausus 48 (holotype BM!). Dasus verticillatus Lour. (1790: 141). Type: — VIETNAM. G. Dausus 48 (holotype BM!). Lasianthus andamanicus Hook.f. (1880: 189). Type:— MYANMAR. Amherst, Tenasserim, Wall. Cat. 8309 (holotype K! [K000031676]). Lasianthus tamirensis Pierre ex Pit. (1924: 390). Type:— CAMBODIA. Samrong-tong, Mt Tamire, May 1870, Pierre 587 (holotype P! [P02285234]; isotype K! [K000777002]). Lasianthus wrayi King & Gamble (1904: 119). Type:— MALAYSIA. Perak, Wray 257 (holotype K! [K000777043]). Specimens examined: — VIETNAM. Northern: Ninh Binh Province, Cuc Phuong National Park, 365 m elev., 18 November 2018, Dang V.S. & Naiki A., Dang 284 & Dang 290 (VNM, the herbarium of Iriomote Station (Japan)). Central: Khanh Hoa Province, Hon Ba Nature Reserve, 910 m elev., 25 July 2018, Dang V.S. & Hoang N.T.B.N., Dang 197 (VNM). Southern : Tay Ninh Province, Logo-Xamat National Park, 10 elev., 22 November 2020, Dang V.S. & Hoang N.S., Dang 435 (VNM). Distribution: —Widespread in the tropical and subtropical regions in Asia (Cambodia, China, India, Indonesia, Japan, Laos, Malaysia, Myanmar, Papua New Guinea, Philippines, Sri Lanka, Thailand). In Vietnam, Lasianthus verticillatus occurs in Dong Nai, Ha Tinh, Khanh Hoa, Kien Giang, Kon Tum, Lam Dong, Ninh Binh, Tay Ninh, and Thua Thien Hue. Habitat & Ecology: —Growing under the shade of primary and secondary forests or in hills and the edge of the evergreen montane forests at 300–1000 m elev. Phenology: —Flowering and fruiting from November to April of the next year. Vernacular name: —Xú hưƠng luân sinh. Notes: —Two Vietnamese species, L. tamirensis Pierre ex Pit. (1924: 390) and L. wrayi King & Gamble (1904: 119) were treated as synonyms of L. verticillatus by Zhu et al. (2012). This species is easily identified in the field in having oblong to oblong-lanceolate leaves, secondary veins 7–9 on each side of midrib, calyx cupular truncate, and fruits subglobose, smooth, black when ripe.Published as part of Dang, Van-Son & Naiki, Akiyo, 2023, A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam, pp. 1921-1935 in Phytotaxa 581 (1) on pages 1921-1935, DOI: 10.11646/phytotaxa.581.1.1, http://zenodo.org/record/757155