Lasianthus inodorus Blume (1826: 998)

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

33. Lasianthus inodorus Blume (1826: 998) — Fig. 56 (plate), Fig. 57 (map)

Type: — INDONESIA. Java, Blume s.n. (holotype L! [L0000690]) .

Lasianthus tubiferus Hook.f. (1880: 183) . Type:— INDIA. Khasia, Hooker & Thomson 9 (lectotype K! [K000031593], designated by Deb & Gangopadhyay 1991; isotype L! [L0000710]).

Lasianthus poilanei Pit. (1924: 398) . Type:— CAMBODIA. Elephant Mountain , 20 May 1921, Poilane 234 (isotype K! [K000777025]).

Specimens examined: — VIETNAM. Central: Khanh Hoa Province, Hon Ba Nature Reserve, 1510 m elev., 23 July 2018, Dang V.S. & Hoang N.T.B.N., Dang 192 ( VNM, the herbarium of Iriomote Station (Japan )); in the same location, 1500 m elev., 20 June 2019, Dang V.S. & Pham Q.T., Dang 342 ( VNM); in the same location, 1524 m elev., 28 November 2017, Dang V.S. & Naiki A. N10119 ( VNM, the herbarium of Iriomote Station (Japan)) .

Distribution: —Widespread in tropical and subtropical regions in Asia ( Bangladesh, Cambodia, China, India, Indonesia, Thailand). In Vietnam, Lasianthus inodorus occurs in Khanh Hoa and Lam Dong.

Habitat & Ecology: —Growing under the canopy of primary and secondary forests at 600–1560 m elev.

Phenology: —Flowering and fruiting from July to November.

Vernacular name: —Xú hưƠng poilane.

Notes: — Lasianthus inodorus was clarified in the revision by Zhu et al. (2012) and a Vietnamese species, L. poilanei Pit. (1924: 398) was treated as the synonym of L. inodorus .

This species is characterized by having elliptic to elliptic-lanceolate leaves, secondary veins 6–7 on each side of midrib, bracts orbicular, 3–7 mm long, calyx campanulate, 5–10 mm long, and fruits ovoid, glabrous, pyrenes 5.