Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam Author Dang, Van-Son Institute of Life Sciences, 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 Author Le, Tuan Anh Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam & Mien Trung Institute for Scientific Research, Vietnam National Museum of Nature, VAST, 321, Huynh Thuc Khang Street, ThuaThien Hue, Vietnam Author Hoang, Thanh Son 0000-0003-0351-929X Silviculture Research Institute, Vietnamese Academy of Forest Sciences, Ha Noi, Vietnam hoangsonfsiv@gmail.com Author Le, Van Son 0000-0003-0151-0646 Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province, Vietnam lvsonplant@gmail.com Author Ha, Van Bac 0009-0009-4010-7981 Forest Protection Department of Dakrong Nature Reserve, Quang Tri Province, Vietnam vanbacha@yahoo.com Author Pham, Quoc Trong 0009-0004-6879-7535 Institute of Life Sciences, Vietnam Academy of Science and Technology, 85 Tran Quoc Toan Street, District 3, Ho Chi Minh City, Vietnam phamquoctrong117@gmail.com Author Phetlasy, Souladeth 0000-0001-8563-1773 Faculty of Forest Science, National University of Laos, Dongdok Campus, Xaythany District, Vientiane Capital, Laos p.souladeth@nuol.edu.la Author Tagane, Shuichiro 0000-0002-1974-7329 The Kagoshima University Museum, Kagoshima University, 1 - 21 - 30, Korimoto, Kagoshima, 890 - 0065, Japan stagane29@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 naiki@lab.u-ryukyu.ac.jp text Phytotaxa 2025 2025-03-18 694 1 57 67 https://doi.org/10.11646/phytotaxa.694.1.4 journal article 10.11646/phytotaxa.694.1.4 1179-3163 16723723 Lasianthus laoticus Tagane, Soulad. & Nob.Tanaka (2023: 148) . Figures 5 & 6 . TYPE :— LAOS . Attapeu Province : Sanamxai District, roadside, at the edge of evergreen forests, 14°47′18.18″N , 106°25′24.90″E , 183 m elevation, 6 July 2019 , P . Souladeth, S . Tagane, N . Tanaka, K . Souttakone, Y . Suyama, K . Phengmala, N . Ishii L 3024 ( holotype FOF !, isotypes KAG [ KAG 129297], TNS !). Distribution, habitat and phenology: — Laos ( Attapeu and Champasak Provinces) and Vietnam (Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province ). It grows in lowland evergreen forests, 20–190 m elev. Flowering and fruiting specimens were collected in July to August. Vernacular name: —Xú hƯƠng lào (Vietnamese). Notes: — Lasianthus laoticus was described from Laos by Tagane et al. (2023) based on two collections, Souladeth et al. L3024 and L2222 . This species is easily recognizable in the field in having brownish hairy branches, cordate leaf base, secondary veins 8–11 pairs, long peduncles 1.5–3 cm long, flowers white with a faint tinge of yellow, and fruits subglobose or ovoid, black when ripe. Specimen examined: — VIETNAM . Ba Ria-Vung Tau Province : Binh Chau-Phuoc Buu Nature Reserve, in evergreen forests, 10°35′12.04″N , 107°33′25.00″E , 28 m elev., 16 August 2022 , V.-S. Dang & L.V. Son Dang-664 (VNM [VNM00070336]).