Lasianthus rhinocerotis Blume (1826: 996)

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

58. Lasianthus rhinocerotis Blume (1826: 996)

subsp. pedunculatus (Pit.) H.Zhu (1998: 154) — Fig. 87 (plate), Fig. 84 (map)

Type: — VIETNAM. Lang Son Province, Cao Loc District, Dong Dang Commune , 10 February 1886, Balansa 638 (holotype P! [P02285237]; isotype L!, P!) .

Lasianthus koi Merr. & Chun (1934: 47) . Type:— CHINA. Hainan, 29 April 1932, S.P. Ko 52243 (holotype IBSC!; isotype K!, US!) .

Lasianthus rhinocerotis var. pedunculatus Pit. (1924: 395) . Type:— VIETNAM. Lang Son Province, Cao Loc District, Dong Dang Commune , 10 February 1886, Balansa 638 (holotype P! [P02285237]; isotype L!, P!).

Specimens examined: — VIETNAM. Central: Ha Tinh Province, Vu Quang National Park, 860 m elev., 26 July 2015, Yahara T., Toyama H., Tagane S., Nguyen N., Yang C.J., Nguyen H. V 3755 & V3805 ( DLU, FU, VNM, the herbarium of Iriomote Station (Japan )); in the same location, 546 m elev., Yahara T., Toyama H., Tagane S., Nguyen N., Yang C.J., Nguyen H. V 3585 ( DLU, FU, the herbarium of Iriomote Station (Japan )) .

Distribution: —Tropical and subtropical regions in Asia ( China). In Vietnam, Lasianthus rhinocerotis subsp. pedunculatus occurs in Ha Tinh and Lang Son.

Habitat & Ecology: —Growing in a hill of the evergreen montane forest at 500–900 m elev. The forest habitats are dominated by species of Fabaceae , Symplocaceae , Euphorbiaceae , Fagaceae , Rubiaceae , Annonaceae , Apocynaceae , Clusiaceae , and Anacardiaceae .

Phenology: —Flowering and fruiting from February to July.

Vernacular name: —Xú hưƠng có cọng.

Notes: — Lasianthus rhinocerotis var. pedunculatus was reported as subspecies of Vietnam by Zhu (1998). This subspecies is easily identified in the field in having oblong-lanceolate or lanceolate leaves, secondary veins 9–10 on each side of midrib, peduncles 2–4 mm long, densely villous, and fruits subglobose or obovate, blue when ripe.

Figures

FIGURE 84. Distribution maps of Lasianthus phamhoangii, L. pierrei, L. repoeuensis and L. rhinocerotis subsp. pedunculatus.

FIGURE 87. Lasianthus rhinocerotis subsp. pedunculatus (Pit.) H.Zhu (A. from V3805 and B–I from V3755, VNM, FU and the herbarium of Iriomote Station (Japan)): A. Branch with flowers, B. Close-up of expanding young leaves, C. Stipules, D. Abaxial leaf surfaces, E. Inflorescence showing lateral view flower buds, F–I. Fruits (A & F: photos by Shuichiro Tagane).