Lasianthus hispidulus (Drake) Pit. (1924: 382)

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

30. Lasianthus hispidulus (Drake) Pit. (1924: 382) — Fig. 53 (plate), Fig. 52 (map)

Type: — VIETNAM. Thai Nguyen Province, Eberhardt 3852 (lectotype P!, designated by Zhu 2001) .

Mephitidia hispidula Drake (1895: 239) . Type: — VIETNAM. Thai Nguyen Province, Eberhardt 3852 (lectotype P!, designated by Zhu 2001).

Lasianthus brevidens Craib (1933: 19) . Type :— THAILAND. Ratchburi, Kerr 10833 (holotype K! [K000777026]).

Lasianthus bunzanensis Simizu (1944: 301) . Type :— CHINA. Taiwan , Taipei, Suzuki 16385 (holotype TI!).

Specimens examined: — VIETNAM. Northern: Thai Nguyen Province, 07 August 1917, 3852 (P) . Central: 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 1072 & V1083 ( 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 1713 ( FU, VNM, the herbarium of Iriomote Station ( Japan)) ; in the same location, 907 m elev., 28 November 2017, Dang V.S. & Naiki A. N10126 ( VNM, the herbarium of Iriomote Station ( Japan)) ; in the same location, 900 m elev., 19 April 2018, Dang V.S. & Hoang N.T.B.N., Dang 185 ( VNM) ; Kon Tum Province, Ngoc Linh Nature Reserve , 1365 m elev., 14 February 2017, Tagane S., Nagamasu H., Nguyen V.N., Hoang T.B., Hoang T.S., Yang C.J., Kawakubo A. V 6555 ( DLU, FU) .

Distribution: —Widespread in tropical and subtropical regions in Asia ( Cambodia, China, Indonesia, Japan, Malaysia, Papua New Guinea, Thailand). In Vietnam, Lasianthus hispidulus occurs in Khanh Hoa, Kon Tum, and Thai Nguyen.

Habitat & Ecology: —Growing under the forest canopy of primary and secondary forests, at 600–1400 m elev.

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

Vernacular name: —Xú hưƠng phún.

Notes: — Lasianthus hispidulus is similar to L. fordii Hance (1885: 324) but differs in its densely hairy branches, leaves abaxially, and calyx. It is closely related to L. curtisii King & Gamble (1904: 128) but differs from the latter in having calyx lobes shorter than calyx tube (vs. longer).

Figures

FIGURE 52. Distribution maps of Lasianthus hirsutus, L. hispidulus, L. honbaensis and L. hongiaoensis.

FIGURE 53. Lasianthus hispidulus (Drake) Pit. (A–C & G–I from Dang 185 and D–F from V1713, VNM and the herbarium of Iriomote Station (Japan)): A. Branch with flower buds, B. Stipules, C. Abaxial leaf surfaces, D–E. Inflorescence showing side view flower buds, F–G. Flowers and young fruits, H. Fruits, I. Seeds.