A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam Dang, Van-Son Naiki, Akiyo Phytotaxa 2023 2023-01-26 581 1 1921 1935 V. S. Dang & Naiki (2021: 17) V. S. Dang & Naiki 17 2021 [178,802,1929,1956] Magnoliopsida Rubiaceae Lasianthus Plantae Gentianales 107 Tracheophyta species nuichuaensis   Type:—  VIETNAM. Ninh Thuan Province, Nui Chua National Park,  260 melev.,  16 August 2019,  Dang V.S.& Naiki A., Dang404( holotype VNM! [ VNM00042926]; isotypes VNM! [ VNM00042927, VNM00042928], the herbarium of Iriomote Station(Japan)).   FIGURE 81.  Lasianthus nuichuaensisV.S.Dang & Naiki(from Dang 404, VNM): A.Fruiting branch, B.Stipules, C.Abaxial leaf surfaces, D–F.Close-up of inflorescences and flowers, G–H.Close-up of immature and mature fruits, I.Seeds.   Specimensexamined:—  VIETNAM. Central: Ninh Thuan Province, Nui Chua National Park,  260 melev., 11°44’06.53’’N, 109°13’15.12’’E, in secondary forest,  16 August 2019,  Dang V.S.& Naiki A., Dang404( VNM, the herbarium of Iriomote Station( Japan)); in the same location,  256 melev., 11°44’06.51’’N, 109°13’15.11’’E, in secondary forest,  01 December 2017,  Dang V.S.& Naiki A. N10147( KYO, VNM, the herbarium of Iriomote Station(Japan)).   Distribution:—Endemic to Vietnam(known only from the Nui Chua National Park, Ninh Thuan Province).  Habitat & Ecology:— This species is only known from the typelocality in Nui Chua National Park, Ninh Thuan Province, southern Vietnamwhere it grows under the shade of the secondary forest at an elevation between  200–300 m.  Phenology:—Flowering from June to September, fruiting from October to December  Vernacular name:—Xú hưƠng núi chúa.  Notes:—  Lasianthus nuichuaensisis closely related to  L. hispidulus(Drake) Pit. (1924: 382)in the shape of leaves, the number of secondary veins and inflorescences, but differs from the latter by having glabrous branches (vs. densely brown-villous), smaller leaves (5–7 × 1.5–3 cmvs. 7–10 × 3–5 cm), bracts 1–1.5 mmlong (vs. absent), calyx and corolla lobes 4 (vs. lobes 5), orange fruits (vs. blue) and drupe with 4 pyrenes (vs. 5 pyrenes). 2019-08-16 VNM Dang V. S. & Naiki A. & Dang Vietnam 260 Iriomote Station Nui Chua National Park 107 VNM00042926, VNM00042927, VNM00042928 1 Ninh Thuan holotype N10147 2017-12-01 2019-08-16 2017-12-01 VNM, KYO Dang V. S. & Naiki A. & Dang & Japan Vietnam Nui Chua National Park 260 11.735142 Iriomote Station 1 109.22086 Iriomote Station 108 1 Ninh Thuan Vietnam 250 Nui Chua National Park 109 1 Ninh Thuan