Lasianthus sonlangensis V.S.Dang, Vuong & Quan (2022: 25)

Dang, Van-Son & Naiki, Akiyo, 2023, A revision of the genus Lasianthus Jack (Rubiaceae) from Vietnam, Phytotaxa 581 (1), pp. 1921-1935 : 1921-1935

64. Lasianthus sonlangensis V.S.Dang, Vuong & Quan (2022: 25) — Fig. 95 (plate), Fig. 94 (map)

Type: — VIETNAM. Gia Lai Province, K’Bang District, Son Lang Commune, Kon Chu Rang Nature Reserve , 900–1100 m elev., 22 April 2021, Van-Son Dang, Ba Vuong Truong, Minh Quan Dang & Nghia Son Hoang, Dang 465 (holotype VNM! [ VNM00042935 ]; isotypes HN!, VNM! [ VNM00042936 , VNM00042937 ]) .

Specimens examined: — VIETNAM. Central: Gia Lai Province, K’Bang District, Son Lang Commune, Kon Chu Rang Nature Reserve , 1080 m elev., 25 April 2021, Van-Son Dang, Ba Vuong Truong, Minh Quan Dang & Nghia Son Hoang, Dang 465a ( VNM) .

Distribution: —Endemic to Vietnam (currently known only from Kon Chu Rang Nature Reserve of Gia Lai Province).

Habitat & Ecology: — Lasianthus sonlangensis occurs in the understory of the primary evergreen forest at an elevation of 900–1100 m.

Phenology: —Flowering and fruiting from March to September.

Vernacular name: —Xú hưƠng sƠn lạng.

Notes: — Lasianthus sonlangensis was described from a Vietnamese specimen (Dang 465) by Dang et al. (2022). It is similar to L. caeruleus Pit. (1924: 390) in the shape of leaves and inflorescences, but differs from the latter in having more than secondary veins, shorter petioles, bracts present (vs. absent), larger calyx and corolla lobes 4 (vs. 5).