34. Lasianthus japonicus Miq. (1867: 110) — Fig. 58 (plate), Fig. 57 (map)

Type: — JAPAN. Nagasaki, October 1962, S. Coll. 949 (isolectotype K! [K000763881]).

Lasianthus hartii Franch. (1899: 209). Type:— CHINA. Fokien, La touche s.n. (holotype P!).

Lasianthus taiheizanensis Masam. & Suzuki (1930: 49). Type:— CHINA. Taiwan, Taiheizan, Suzuki s.n. (holotype TI!).

Lasianthus japonicus var. lancilimbus (Merr.) H.S.Lo (1999: 99). Type:— CHINA. Kwangtung, Nam Kwan Shan, Tsang 20293 (holotype IBSC!; isotype K!, NY!).

Lasianthus lucidus Blume (1826: 997) var. caudisepalus Deb & M.Gangop. (1991: 292). Type:— INDIA. Assam, Cox & Hutchinson 499 (holotype K!; isotype E!).

Specimens examined: — VIETNAM. Norther: Vinh Phuc Province, Tam Dao National Park, 1124 m elev., 13 November 2018, Dang V.S. & Naiki A., Dang 236 & Dang 251 (VNM, the herbarium of Iriomote Station (Japan)).

Central: Thua Thien Hue Province, Bach Ma National Park, 1193 m elev., 26 July 2019, Dang V.S. & Naiki A., Dang 372 & Dang 415 (VNM, the herbarium of Iriomote Station (Japan)).

Distribution: —Widespread in tropical and subtropical regions in Asia (China, India, Japan). In Vietnam, Lasianthus japonicus occurs in Thua Thien Hue, anh Vinh Phuc.

Habitat & Ecology: —Growing under evergreen forest and the edges of the forest at 900–1200 m elev.

Phenology: —Flowering and fruiting from July to December.

Vernacular name: —Xú hưƠng nhật.

Notes: — Lasianthus japonicus is easily identified in the field in having oblong to oblong-lanceolate leaf blade, secondary veins 5–7 on each side of midrib, inflorescences congested-cymose, calyx purple, corolla white at anthesis, and fruits globose, blue to blackish when ripe.