Lasianthus laoticus Tagane, Soulad. & Nob.Tanaka (2023: 148)

Dang, Van-Son, Le, Tuan Anh, Hoang, Thanh Son, Le, Van Son, Ha, Van Bac, Pham, Quoc Trong, Phetlasy, Souladeth, Tagane, Shuichiro & Naiki, Akiyo, 2025, Two new species and one new addition of Lasianthus (Rubiaceae) for the flora of Vietnam, Phytotaxa 694 (1), pp. 57-67 : 64

Lasianthus laoticus Tagane, Soulad. & Nob.Tanaka (2023: 148) . Figures 5 & 6 .

TYPE:— LAOS. Attapeu Province: Sanamxai District, roadside, at the edge of evergreen forests, 14°47′18.18″N, 106°25′24.90″E, 183 m elevation, 6 July 2019, P. Souladeth, S. Tagane, N. Tanaka, K. Souttakone, Y. Suyama, K. Phengmala, N. Ishii L 3024 (holotype FOF!, isotypes KAG [ KAG 129297], TNS!).

Distribution, habitat and phenology: — Laos (Attapeu and Champasak Provinces) and Vietnam (Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province). It grows in lowland evergreen forests, 20–190 m elev. Flowering and fruiting specimens were collected in July to August.

Vernacular name: —Xú hƯƠng lào (Vietnamese).

Notes: — Lasianthus laoticus was described from Laos by Tagane et al. (2023) based on two collections, Souladeth et al. L3024 and L2222. This species is easily recognizable in the field in having brownish hairy branches, cordate leaf base, secondary veins 8–11 pairs, long peduncles 1.5–3 cm long, flowers white with a faint tinge of yellow, and fruits subglobose or ovoid, black when ripe.

Specimen examined: — VIETNAM. Ba Ria-Vung Tau Province: Binh Chau-Phuoc Buu Nature Reserve, in evergreen forests, 10°35′12.04″N, 107°33′25.00″E, 28 m elev., 16 August 2022, V.-S. Dang & L.V. Son Dang-664 (VNM [VNM00070336]).

Figures

FIGURE 5. Specimen of Lasianthus laoticus Tagane, Soulad. & Nob.Tanaka (Dang 664, VNM). Photoed by Van-Son Dang.

FIGURE 6. Lasianthus laoticus Tagane, Soulad. & Nob.Tanaka, A. Habit, B. Branch, C. Shoot apex showing expanding young leaves, D. Stipule, E. Abaxial leaf surface, F–G. Inflorescences and flowers, H. Young fruit, I. Mature fruit. Photoed by Van-Son Dang.