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 23. Lasianthus fordii Hance (1885: 324) — Fig. 44 (plate), Fig. 42 (map) Type: — CHINA . Guangdong , Lo Fau Shan , 244 m elev., August 1883 , S. Coll. 66 ( holotype BM! [ BM000945611 ]; isotype K! [K000763821]) . Lasianthus zambalensis Elmer (1934: 3209) . Type :—PHILLIPPINES. Camp Stotsenburg , Pinatubo mountain , Pampanga Province , Luzon , May 1927 , Elmer 22045 (isotype K! [K000777092]). Lasianthus kamputensis Pierre ex Pit. (1924: 392) . Type :— VIETNAM , Quang Tri Province , 3 April 1913 , Eberhardt 2050 ( syntype P!). Specimens examined: — VIETNAM . Northern: Thai Nguyen Province , Vo Nhai District , La Hien Commune, P 3886 ( VNM ); Vinh Phuc Province , Tam Dao National Park , 925 m elev., 13 November 2018 , Dang V.S. & Naiki A. , Dang 235 ( VNM , the herbarium of Iriomote Station ( Japan )) . Central: Ha Tinh Province , Vu Quang National Park , 914 m elev., 26 July 2015 , Yahara T. , Toyama H. , Tagane S. , Nguyen N. , Yang C.J. , Nguyen H. V 3778 ( DLU , FU , the herbarium of Iriomote Station (Japan)); Khanh Hoa Province , Hon Ba Nature Reserve , 900 m elev., 19 April 2018 , Dang V.S. & Hoang N.T.B.N. , Dang 183 ( VNM ) . Southern: Dong Nai Province , Bien Hoa District , June 1909 , Sno (P) . Distribution: —Widespread in tropical and subtropical regions in Asia ( Cambodia , China , India , Indonesia , Japan , Papua New Guinea , Philippines , Thailand ). In Vietnam , Lasianthus fordii occurs in Bac Kan , Dong Nai , Gia Lai , Ha Tinh , Khanh Hoa , Lam Dong , Lao Cai , Quang Tri , Tay Ninh , Thai Nguyen , Thua Thien Hue and Vinh Phuc . Habitat & Ecology: —Growing under shade or on the edge of evergreen forest, at 600–1200 m elev. Phenology: —Flowering and fruiting from July to November. FIGURE 43. Lasianthus foetidissimus A.Chev. ex Pit. (from Dang 343 , VNM and the herbarium of Iriomote Station (Japan)): A. Branch with flowers and bubs, B. Stipules, C. Abaxial leaf surfaces, D–E. Inflorescence showing side view buds and flower, F. Flower, G. Flower buds and fruit, H. Young fruits, I. Mature fruits. FIGURE 44. Lasianthus fordii Hance (from Dang 235 , VNM and the herbarium of Iriomote Station (Japan)): A. Branch with flowers and fruits, B. Stipules, C. Abaxial leaf surfaces, D–F. Inflorescence showing side view buds and flowers, G. Flower, young and mature fruits, H. Mature fruits, I. Cross section of fruit with pyrenes. Vernacular name: —Xú hưƠng lưỡi vành. Notes: — Lasianthus fordii was clarified in the revision by Zhu et al. (2012) and a Vietnamese species, L. kamputensis Pierre ex Pit. (1924: 392) was treated as the synonym of L. fordii . Lasianthus fordii is very close to L. formosensis Matsum. (1901: 17) based on its shape of leaf blades, inflorescences and indumentum, but differs from the latter in having triangular calyx lobes obviously shorter than the tube (vs. lanceolate calyx lobes longer than tube).