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 38. Lasianthus konchurangensis V.S.Dang, T.B.Tan & T.D. Ha (2020: 163) — Fig. 63 (plate), Fig. 62 (map) Type: — VIETNAM . Gia Lai Province , K’Bang District , Kon Chu Rang Nature Reserve , 1012 m elev., 25 July 2017 , Do.V.H. , Bui H.Q. , Duong T.H. , Dong H.S. & Tran D.B. , KCR 011 ( holotype HN ! [ HN0000070168 ]; isotypes HN ! [ HN0000070169 ], VNM ! [ VNM00042907 , VNM00042908 ]) . FIGURE 63. Lasianthus konchurangensis V.S.Dang, T.B.Tran & T.D.Ha (A–B & G–J from V10202 and C–F from KCR 011 , HN and VNM): A. Branch with flowers, B. Close-up of expanding young leaves, C. Stipules, D. Abaxial leaf surfaces, E–F. Inflorescences, G. Flower, H–J. Fruits ( A–B & G–J : photos by Shuichiro Tagane and C–F : photos by Do Van Hai). Specimens examined: — VIETNAM . Central: Gia Lai Province , K’Bang District , Kon Chu Rang Nature Reserve , 1022 m elev., 19 August 2019 , Oguri E. , Tagane S. , Sugai K. , Suyama Y. & Bui H.Q. V10202 ( HN , VNM ) . Distribution: —Endemic to Vietnam (currently known only from Kon Chu Rang Nature Reserve of Gia Lai Province ). Habitat & Ecology: — Lasianthus konchurangensis is easily found in primary evergreen forests at 1000–1030 m elev. Phenology: —Flowering and fruiting from June to November. Vernacular name: —Xú hưƠng kon chư răng. Notes: — Lasianthus konchurangensis is similar to L. foetidissimus A.Chev. ex Pit. (1924: 395) which is endemic to Vietnam , but differs from the latter in having a leaf blade 16–25 × 3–4.5 cm (vs. 11–14 × 2–3 cm ), secondary veins 9–14 on each side of midrib (vs. 6), petioles 12–18 mm long (vs. 9–12 mm long), calyx tube 2–3 mm long (vs. 1.25 mm long) and calyx lobes 2–2.5 mm long (vs. 0.25 mm long), corolla tube 6.5–7 mm long (vs. up to 6 mm long) and corolla lobes 2–3 mm long (vs. 2 mm long), fruits black (vs. yellow to wish-orange) and pyrenes 4 (vs. 5). It is also similar to L. japonicus Miq. (1867: 110) , but differs from the latter in having petioles 12–18 mm long (vs. 3–10 mm long), secondary veins 9–14 on each side of midrib (vs. 5–7), and corolla tube 6.5–7 mm long (vs. 9–10 mm long) and corolla lobes 2–3 mm long (vs. 4–4.5 mm long).