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 33. Lasianthus inodorus Blume (1826: 998) — Fig. 56 (plate), Fig. 57 (map) Type: — INDONESIA . Java , Blume s.n. ( holotype L! [L0000690]) . Lasianthus tubiferus Hook.f. (1880: 183) . Type:— INDIA . Khasia, Hooker & Thomson 9 ( lectotype K! [K000031593], designated by Deb & Gangopadhyay 1991 ; isotype L! [L0000710]). Lasianthus poilanei Pit. (1924: 398) . Type :— CAMBODIA . Elephant Mountain , 20 May 1921 , Poilane 234 (isotype K! [K000777025]). Specimens examined: — VIETNAM . Central: Khanh Hoa Province , Hon Ba Nature Reserve , 1510 m elev., 23 July 2018 , Dang V.S. & Hoang N.T.B.N. , Dang 192 ( VNM , the herbarium of Iriomote Station ( Japan )); in the same location, 1500 m elev., 20 June 2019 , Dang V.S. & Pham Q.T. , Dang 342 ( VNM ); in the same location, 1524 m elev., 28 November 2017 , Dang V.S. & Naiki A. N10119 ( VNM , the herbarium of Iriomote Station (Japan)) . Distribution: —Widespread in tropical and subtropical regions in Asia ( Bangladesh , Cambodia , China , India , Indonesia , Thailand ). In Vietnam , Lasianthus inodorus occurs in Khanh Hoa and Lam Dong . Habitat & Ecology: —Growing under the canopy of primary and secondary forests at 600–1560 m elev. Phenology: —Flowering and fruiting from July to November. Vernacular name: —Xú hưƠng poilane. Notes: — Lasianthus inodorus was clarified in the revision by Zhu et al. (2012) and a Vietnamese species, L. poilanei Pit. (1924: 398) was treated as the synonym of L. inodorus . This species is characterized by having elliptic to elliptic-lanceolate leaves, secondary veins 6–7 on each side of midrib, bracts orbicular, 3–7 mm long, calyx campanulate, 5–10 mm long, and fruits ovoid, glabrous, pyrenes 5.