A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam Dang, Van-Son Naiki, Akiyo Phytotaxa 2023 2023-01-26 581 1 1921 1935 3SCHV Pitard (1924: 390) Pitard 390 1924 [164,625,1857,1884] Magnoliopsida Rubiaceae Lasianthus Plantae Gentianales 29 Tracheophyta species caeruleus   Type:—  VIETNAM. Lao Cai Province, Sapa,  1400–1500 melev.,  6 December 1913,  A. Chevalier29398( holotypeP! [P04009929]).   Specimensexamined:—  VIETNAM. Central: Thua Thien Hue Province, Bach Ma National Park,  1193 melev.,  26 July 2019,  Dang V.S.& Naiki A., Dang407 & Dang411( VNM, the herbarium of Iriomote Station(Japan)); Da NangCity, Ba Na Nature Reserve,  1480 melev.,  26 June 2019,  Dang V.S.& Hoang N.S., Dang 373( VNM); in the same location,  1489 melev.,  27 July 2019,  Dang V.S.& Naiki A., Dang420( VNM, the herbarium of Iriomote Station( Japan)).   Distribution:—Endemic to Vietnam(currently known as Sapa District in Lao Cai Province, Bach Ma National Park in Thua Thien Hue Province, Ba Na Nature Reserve in Da NangCity, and Kon Chu Rang Nature Reserve in Gia Lai Province).   FIGURE 21.  Lasianthus caeruleusPit.(A–G from Dang 411and H–J from Dang 407, VNM and the herbarium of Iriomote Station (Japan)): A.Habit, B.Fruiting branch, C.Stipules, D.Abaxial leaf surfaces, E–G.Inflorescence showing lateral view flowers and buds, H–J.Young fruits.  Habitat & Ecology:—Growing in primary and secondary montane forests or on the edge of the forest, on gravel soil at 1200–1600 melev. This species was found in the forest habitats where  Lasitnhus japonicusMiq. (1867: 110),  Crotonsp.,  Phyllanthus reticulatusPoir. (1804: 298),  Streblus indicus(Bureau) Corner (1962: 226),  Melastoma malabathricumL. (1753: 390),  Anomianthussp.,  Rubus pluribracteatusL.T.Lu & Boufford (2003: 255)are dominant.  Phenology:—Flowering and fruiting from June to December.  Vernacular name:—Xú hưƠng lam.  Notes:—  Lasianthus caeruleuswas described in 1924 from a Vietnamese specimen ( A. Chevalier 29398). This species was characterized in the field as having yellowish-green, velvety branches and then black, pubescent ones. [219,1412,1897,1919] 1913-12-06 A. Chevalier Vietnam 1450 Sapa 29 1 Lao Cai holotype 2019-06-26 2019-07-27 2019-06-26 VNM Dang V. S. & Naiki A. & Dang & Hoang N. S. & Japan Vietnam Thua Thien Hue Province 1193 30 Iriomote Station Bach Ma National Park 29 1 Da Nang