Lasianthus saxorum Craib (1933: 25)

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

61. Lasianthus saxorum Craib (1933: 25) — Fig. 91 (plate), Fig. 89 (map)

Type: — THAILAND. Loei, Phu Kradung , 10 February 1931, A.F.G.Kerr 20055 (holotype K! [K000777007]; isotype PK! [ PK257395 ].

Specimens examined: — VIETNAM. Central: Ha Tinh Province, Vu Quang National Park, 1627 m elev., 18˚11’57.09”N, 105˚23’09.07’’E, in lower montane forest, 22 June 2016, Yahara T., Nguyen N., Toyama H., Tagane S., Okabe N., Nguyen H. V 5759 ( DLU, FU, VNM, the herbarium of Iriomote Station (Japan )) .

Distribution: —Indochina region ( Thailand). In Vietnam, Lasianthus saroxum occurs in Ha Tinh.

Habitat & Ecology: —In shaded places on lower montane of evergreen forests at 1200–1700 m elev.

Phenology: —Flowering from February to June, fruiting from June to October.

Vernacular name: —Xú hưƠng đá.

Notes: — Lasianthus saroxum is a new record for the flora of Vietnam. This species is characterized by having appressed pubescent branches; leaves oblong-lanceolate, 7–8 × 2–3, the apex caudate, the base cuneate; petioles 3–4 mm long; stipules small, 1–2 mm long, puberulous; calyx appressed pubescent, calyx lobes obviously shorter than the tube; fruit fuscous-puberulous, pyrenes 5.

Figures

FIGURE 89. Distribution maps of Lasianthus sapaensis, L. saprosmoides, L. saxorum and L. schmidtii.

FIGURE 91. Lasianthus saxorum Craib (from V5759, FU, VNM and the herbarium of Iriomote Station (Japan)): A. Branch with fruits, B. Close-up of expanding young leaves, C. Stipules, D. Abaxial leaf surfaces, E–F. Inflorescence showing side view buds and flowers, G–I. Fruits (A, F–I: photos by Shuichiro Tagane).