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 72. Lasianthus viridiramulis Tagane (2015:173) — Fig. 105 (plate), Fig. 104 (map) Lasianthus brevipes Craib (1933: 20) , nom. illeg.; Saprosma brevipes H. Zhu (2001: 148) ; Paralasianthus brevipes (H. Zhu) H. Zhu (2015: 275) . Type: — THAILAND . Nakhon Si Thammarat , 10 May 1928 , A.F.G.Kerr 15641 (( holotype K! [K000777001]). Specimens examined: — VIETNAM . Central: Khanh Hoa Province , Hon Ba Nature Reserve , 617 m elev., 21 February 2014 , Toyama H. , Dang V.S. , Tagane S. , Fuse K. , Yahara T. , Nagamasu H. , Tran H. with Ngoc N.V. , Cuong N.Q. , Thach N.D. , Hieu H.N.P. V 1209 ( FU , VNM , the herbarium of Iriomote Station (Japan)); in the same location, 619 m elev., 16 June 2019 , Dang V.S. & Hoang N.T.B. N., Dang 363 ( VNM , the herbarium of Hon Ba Nature Reserve ) . Distribution: —Southeast Asia region ( Cambodia , Thailand ). In Vietnam , Lasianthus viridiramulis occurs in Hon Ba Nature Reserve of Khanh Hoa Province . Habitat & Ecology: —This species was found under the canopy of the evergreen forest at around 600–800 m elev. Phenology: —Flowering and fruiting from June to September. Vernacular name: —Xú hưƠng xanh lục. Notes: — Lasianthus viridiramulis is a new record for the flora of Vietnam . This name is accepted in a publication based on molecular evidence by Naiki et al. (2015) . It is characterized in having elliptic to lanceolate leaves, secondary veins 8–10 on each side of midrib, flowers pedicellate, calyx greenish white and corolla white, and fruits ovoid with 2 pyrenes.