Lasianthus lancifolius Hook. f. 1880

42. Lasianthus lancifolius Hook.f. (1880: 187) — Fig. 68 (plate), Fig. 67 (map) Type: — INDIA. Khasia, Hooker & Thomson 12 (lectotype K! [K000031624], designated by Deb 1991). Specimens examined: — VIETNAM. Northern: Ha Noi City, Ba Vi National Park, 1267 m elev., 17 November 2018, Dang V.S. & Naiki A., Dang 272 (VNM, the herbarium of Iriomote Station (Japan)); in the same location, 1210 m elev., 17 November 2018, Dang V.S. & Naiki A., Dang 272a (VNM, the herbarium of Iriomote Station (Japan)). Distribution: —Widespread in tropical and subtropical regions in Asia (Bangladesh, Bhutan, China, India, Thailand). In Vietnam, Lasianthus lancifolius occurs in Ha Noi, Phu Tho, and Vinh Phuc. Habitat & Ecology: —Growing under the shade of secondary forest at 1000–1300 m elev. This species is found in the forest where dominated by species Lasianthus thuyanae V.S. Dang & Naiki (2020: 49), L. tamdaoensis V.S. Dang & Naiki (2020: 51), L. fordii Hance (1885: 324), Phyllanthus sp., Melastoma sp., Magnolia cavaleriei (Finet & Gagnep.) Figlar (2000: 21), Asarum maximum Hemsl. (1890: 422), Quercus myrsinifolia Blume (1851: 305), Castanopsis fissa Rehder&E.H.Wilson(1916:203), Cinnamomum balansae Lecomte(1913:75), Magnolia fordiana Hu(1924:228), Madhuca pasquieri H.J.Lam (1925: 182), Markhamia stipulata Seem. (1863: 226), Eberhardtia tonkinensis Lecomte (1920: 346). Phenology: —Flowering and fruiting from September to December. Vernacular name: —Xú hưƠng lá ngọn giáo. Notes: — Lasianthus lancifolius was described in 1880 by Hooker. It is characterized by having lanceolate to elliptic-lanceolate leaves, secondary veins 8–9 on each side of midrib, corolla puberulous outside and pubescent inside, lobes 5, and fruits globose, 3–5 mm diam. In Vietnam, we collected this species on the way to the highest peak in the montane natural forest of Ba Vi National Park at 1210 and 1267 m elev.Published as part of Dang, Van-Son & Naiki, Akiyo, 2023, A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam, pp. 1921-1935 in Phytotaxa 581 (1) on pages 1921-1935, DOI: 10.11646/phytotaxa.581.1.1, http://zenodo.org/record/757155