A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam Author Dang, Van-Son 0000-0001-8681-4141 Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, 870 Uehara, Taketomi-cho, Yaeyama-gun, Okinawa, 907 - 1541 Japan. & Institute of Tropical Biology, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, District 3, Ho Chi Minh City, Vietnam. & Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam. & dvsonitb @ gmail. com; https: // orcid. org / 0000 - 0001 - 8681 - 4141 dvsonitb@gmail.com Author Naiki, Akiyo 0000-0002-3235-2823 Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, 870 Uehara, Taketomi-cho, Yaeyama-gun, Okinawa, 907 - 1541 Japan. & Iriomote Station, Tropical Biosphere Research Center, University of the Ryukyus, 870 Uehara, Taketomi-cho, Yaeyama-gun, Okinawa, 907 - 1541 Japan. & naiki @ lab. u-ryukyu. ac. jp; https: // orcid. org / 0000 - 0002 - 3235 - 2823 * Author for correspondence naiki@lab.u-ryukyu.ac.jp text Phytotaxa 2023 2023-01-26 581 1 1921 1935 http://dx.doi.org/10.1094/PDIS-04-22-0755-PDN journal article 10.11646/phytotaxa.581.1.1 1179-3163 7571550 62. Lasianthus schmidtii K.Schum. (1902: 340) — Fig. 92 (plate), Fig. 89 (map) Type: — THAILAND . Trat , Koh Chang island , 1 March 1900 , Schmidt 6676 ( holotype C! [C10018245]) . Lasianthus kerrii Craib (1911: 396) . Type :— THAILAND . Chiang Mai , Doi Suthep , 20 October 1910 , Kerr 1501 ( holotype K! [K000777023]; isotype BM! [ BM001191354 ]). FIGURE 92. Lasianthus schmidtii K.Schum. (A & D from Dang 302bis, B & E–G from Kerr 1501 and C, & H–I from Schmidt 6676 , VNM, P and C): A. Branch, B. Stipules, C–D. Adaxial leaf surfaces, E–F. Inflorescence showing lateral view buds and flower, G–I. Fruits. Specimens examined: — VIETNAM . Central: Dak Nong Province , Gia Nghia District , 810 m elev., 9 May 2019 , Dang V.S. & Hoang N.S. , Dang 302bis ( VNM ) . Distribution: —Widespread in the tropical and subtropical regions in Asia ( China , Thailand ). In Vietnam , Lasianthus schmidtii occurs in Dak Nong and Lam Dong . Habitat & Ecology: —Growing in the shade of the evergreen forest and the hill or edge of the evergreen montane forest at 700–1200 m elev.. This species was collected from forest habitats where dominated by Lasianthus chrysoneurus (Korth.) Miq. (1857: 322) , Goniothalamus sp. , Dracaena elliptica Thunb. (1808: 6) , Garcinia sp. , Tetracera indica (Christm. & Panz.) Merr. (1917: 367) , Mallotus paniculatus (Lam.) Müll.Arg. (1865: 189), Gnetum latifolium Blume (1834: 162) , Memecylon chevalieri Guillaumin (1921: 7) , Rhodamnia dumetorum (DC.) Merr. & L.M.Perry (1938: 195) , Ardisia crenata Sims (1817: 1950) , Melicope pteleifolia (Champ. ex Benth.) T.G.Hartley (1993: 521) , Leea aequata L. (1767: 627), Camellia chrysantha (Hu) Tuyama (1975: 299) , Smilax glabra Roxb. (1832: 792) . Phenology: —Flowering and fruiting from October to May next year. Vernacular name: —Xú hưƠng schmidt. Notes: — Lasianthus schmidtii was described in 1902 by Schumann. It was clarified in the revision by Zhu and Taylor (2011) and a Vietnamese species, L. kerrii Craib (1911: 396) was treated as the synonym of L. schmidtii . This species is easily identified in the field in having densely tomentose on branches, oblanceolate, oblong or elliptic-oblanceolate leaves, secondary veins 5–7 on each side of midrib, bracts 4–6 mm long, flower white, and fruits subglobose, crowned by calyx lobes, pyrenes 4.