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: 32) V. S. Dang & Naiki 32 2021 [178,802,1942,1969] Magnoliopsida Rubiaceae Lasianthus Plantae Gentianales 74 Tracheophyta species hongiaoensis   Type:—  VIETNAM. Lam Dong Province, Bidoup Nui Ba National Park,  1698 melev.,  24 February 2016,  Tagane S., Nagamasu H., Naiki A., Dang V.S., Nguyen   V.N., Wai J. V4318( holotype VNM![ VNM00042898]; isotypes FU!, VNM! [ VNM00042899, VNM00042900], the herbarium of Iriomote Station( Japan)).   FIGURE 55.  Lasianthus hongiaoensisV.S.Dang & Naiki(from V4318, VNM): A.Branch with fruits, B.Close-up of expanding young leaves, C.Stipules, D.Abaxial leaf surfaces, E.Flower buds and young fruit, F.Inflorescence showing side view flowers, G–H.Fruits, J.Seeds ( E–F: photos by Shuichiro Tagane).   Specimensexamined:—  VIETNAM. Central: Lam Dong Province, Bidoup Nui Ba National Park,  1698 melev., 12°09’52.95’’N, 108°32’00.38’’E, in hill evergreen forests,  24 February 2016,  Tagane S., Nagamasu H., Naiki A., Dang V.S., Nguyen   V.N., Wai J. V4318( FU, VNM, the herbarium of Iriomote Station( Japan)); in the same location,  1490 melev., 12°10’26.91’’N, 108°41’53.94’’E, in evergreen forests,  19 February 2014,  ToyamaH., 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.  V1842( FU, VNM, the herbarium of Iriomote Station( Japan)).   Distribution:—Endemic to Vietnam(known only from the Bidoup Nui Ba National Park, Lam Dong Province).  Habitat & Ecology:—In hill evergreen forest at around 1400–1700 melev.  Phenology:—Flowering and fruiting from February to June.  Vernacular name:—Xú hưƠng hòn giao.  Note:—  Lasianthus hongiaoensisis morphologically similar to  L. hispidulus(Drake) Pit. (1924: 382)in the shape of leaves, flower color at anthesis, and blue fruits, but differs from the latter in having densely pubescent at branches and branchlets (vs. densely brown-villous), longer stipules ( 1–1.5 mmlong vs. 1 mmlong) and larger calyx ( 1.5–2 mmlong vs. 1–1.5 mmlong for tubes and 1.5–2 mmlong vs. 1–1.5 mmlong for lobes). It is also similar to  L. nuichuaensisV.S.Dang & Naikiwhich was described from Nui Chua National Park, Ninh Thuan Province, Southern Vietnam, but differs from the latter by having plants covered by densely pubescent (vs. glabrous), larger leaves (7–9 × 2.5–3.5 cmvs. 5–7 × 1.5–3 cm), fewer secondary veins (4–5 on each side of midrib vs. 5–6 on each side of midrib), larger calyx lobes ( 1.5–2 mmlong vs. 0.5–1 mmlong) and fruits with 5 (vs. 4) pyrenes. 2016-02-24 Tagane S. & Nagamasu H. & Naiki A. & Dang V. S. & Nguyen Vietnam 1698 Bidoup Nui Ba National Park 74 1 Lam Dong VNM, FU Wai J. V Japan Iriomote Station 74 VNM00042898, VNM00042899, VNM00042900 1 holotype 2016-02-24 Tagane S. & Nagamasu H. & Naiki A. & Dang V. S. & Nguyen Vietnam 1698 12.164708 Bidoup Nui Ba National Park 1 108.53344 75 1 Lam Dong 1842-05 2014-02-19 1842-05 FU, VNM Wai J. V & Tagane S. & Dang V. S. & Nagamasu H. & Naiki A. & Tran H. & Yang C. J. & Ngoc N. V. & Cuong N. Q. & Hieu H. N. P. & Loi X. N. Japan 1490 76 12.174142 Iriomote Station 1 108.69832 Iriomote Station 75 1 Toyama