Lasianthus curtisii King & Gamble (1904: 128)

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

15. Lasianthus curtisii King & Gamble (1904: 128) — Fig. 34 (plate), Fig. 32 (map) Type: — MALAYSIA. Penang, Timur Laut, Western Hill , Curtis 284 (lectotype SING! [ SING0059250 ], designated by Zhu 2002). Lasianthus pseudolucidus King & Gamble (1904: 128) . Type :— MALAYSIA. Perak, May 1892, Wray 4109 (isotype SING!

[SING0059235]). Lasianthus kwangtungensis Merr. (1929: 323) . Type:— CHINA. Hong Kong, 3 April 1928, Tsiang 55 (isotype K! [K000763829]). Lasianthus condorensis Pierre ex Pit. (1924: 385) . Type:— VIETNAM. Ha Noi City, Ba Vi mountain, 1887, Balansa 2658 (syntype P!);

Baria—Vung Tau, Con Dao, September 1876, Harmand 916 (syntype P!).

Specimens examined: — VIETNAM. Northern: Vinh Phuc Province, Tam Dao National Park, 782 m elev., 16 November 2018, Dang V.S. & Naiki A., Dang 264 ( VNM, the herbarium of Iriomote Station (Japan)) . Central: Lam Dong Province, 05 June 1933, Poilane 22605 (P); Quang Nam Province, 500 m elev., 21 March 1939, Poilane 29486 (P); Khanh Hoa Province, Hon Ba Nature Reserve , 919 m elev., 21 February 2014, Toyama H., Dang V.S., Tagane S., Fuse K., Yahara T., Nagamasu H., Tran H. with Loi X.N., Thach N.D., Hieu P.N.H. V 1055 ( FU, VNM); in the same location, 900 m elev., 13 July 2014, Tagane S., Kanemitsu H., Dang V.S., Tran H. with Ngoc N.V., Cuong N.Q., Thi D.N., Hieu P.N.H. V 1712 ( FU, VNM); in the same location, 900 m elev., 20 April 2018, Dang V.S. & Hoang N.T.B.N., Dang 182 ( VNM) . Southern: Ba Ria—Vung Tau Province, Con Dao District , September 1876, Harmand 6171 (P) .

Distribution: —Widespread in tropical and subtropical regions in Asia ( Cambodia, China, Indonesia, Japan, Malaysia, Thailand). In Vietnam, Lasianthus curtisii occurs in Ba Ria—Vung Tau, Ha Noi, Khanh Hoa, Kon Tum, Lam Dong, Quang Binh, Quang Tri, Thua Thien Hue, and Vinh Phuc.

Habitat & Ecology: —Growing in primary and secondary forests at 300–1200 m elev.

Phenology: —Flowering and fruiting from July to February of the next year.

Vernacular name: —Xú hưƠng côn sƠn.

Notes: —A Vietnamese species, L. condorensis Pierre ex Pit. (1924: 385) was treated as the synonym of L. curtisii by Zhu et al. (2012). Lasianthus curtisii is easily identified in the field in having calyx lobes longer than calyx tube, corolla white; fruits ovoid-globose, and blue when ripe.

Figures

FIGURE 32. Distribution maps of Lasianthus chinensis, L. chrysoneurus, L. curtisii and L. dakglaiensis.

FIGURE 34. Lasianthus curtisii King & Gamble (from Dang 264, VNM and the herbarium of Iriomote Station (Japan)): A. Branch with flowers and fruits, B. Stipules, C. Abaxial leaf surfaces, D–F. Inflorescence showing side view calyx and flowers, G. Young fruits, H. Mature fruits, I. Seeds.