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 11.2. Lasianthus chevarieli subsp. gianglyensis V.S.Dang & Naiki (2021: 56) — Fig. 29 (plate), Fig. 25 (map) Type: — VIETNAM . Lam Dong Province , Bidoup Nui Ba National Park , 1490 m elev., 19 February 2014 , Toyama H. , Tagane S. , Dang V.S. , Nagamasu H. , Naiki A. , Tran H. , Yang C.J. with Ngoc N.V. , Cuong N.Q. , Hieu H.N.P. , Loi X.N. V1823 ( holotype VNM ! [ VNM00042878 ]; isotypes FU !, VNM ! [ VNM00042879 , VNM00042880 ], the herbarium of Iriomote Station (Japan). Specimens examined: — VIETNAM . Central: Lam Dong Province , Bidoup Nui Ba National Park , 1490 m elev., 12°10’26.91’’N , 108°41’53.94’’E , in evergreen forests, 19 February 2014 , Toyama H. , Tagane S. , Dang V.S. , Nagamasu H. , Naiki A. , Tran H. , Yang C.J. with Ngoc N.V. , Cuong N.Q. , Hieu H.N.P. , Loi X.N. V1823 ( FU , VNM ) . Distribution: —Endemic to Vietnam (known only from the Bidoup Nui Ba National Park, Lam Dong Province ). Habitat & Ecology: —In evergreen forests at 1300–1500 m elev. Phenology: —Flowering and fruiting from February to June. Vernacular name: —Xú hưƠng giang ly. Notes: — Lasianthus chevalieri subsp. gianglyensis is similar to L. chevalieri subsp. chevalieri based on leaf and inflorescences shapes, but differs from the latter in having fewer secondary veins (7–9 on each side of midrib vs. 11 on each side of midrib), shorter petioles ( 5–8 mm long vs. 10–15 mm long), bracts 1.5–2.5 mm long (vs. inconspicuous), smaller corolla ( 11–12 mm long vs. 12–13 mm long for tubes, 4–5 mm long vs. 7–8 mm long for lobes) and yellowishwhite (vs. orange) when ripe.