Lasianthus candidus V.S.Dang, Naiki & Yahara

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

9.1. Lasianthus candidus V.S.Dang, Naiki & Yahara subsp. candidus (2021: 52) — Fig. 24 (plate), Fig. 25 (map) Type: — VIETNAM. Ha Tinh Province, Vu Quang National Park , 1760 m elev., 23 June 2016, Yahara T., Nguyen N., Toyama H., Tagane S.,

Okabe N., Nguyen H. V5877 ( holotype VNM! [ VNM00042876 ]; isotype DLU!, FU!, the herbarium of Iriomote Station ( Japan)) .

Specimens examined: — VIETNAM. Central: Ha Tinh Province, Vu Quang National Park , 1760 m elev., 18˚11’41.09”N, 105˚23’06.08’’E, in lower montane forest, 23 June 2016, Yahara T., Nguyen N., Toyama H., Tagane S., Okabe N., Nguyen H. V 5877 ( VNM) .

Distribution: —Endemic to Vietnam (known from the Vu Quang National Park, Ha Tinh Province).

Habitat & Ecology: —In lower montane of evergreen forests at 1600–1800 m elev.

Phenology: —Flowering from May to July. Fruits not seen. Vernacular name: —Xú hưƠng hoa trắng. Notes: — Lasianthus candidus is similar to L. henryi Hutch. (1916: 401) which is endemic to China based on leaf and inflorescences shapes, but differs from the latter in having fewer secondary veins (5–6 on each side of midrib vs. 7–8 on each side of midrib), longer petioles (8–10 mm long vs. 3–8 mm long), larger stipules (1.5–2 mm long vs. 0.5–1.2 mm long), and larger calyx tubes (1.5–2 mm long vs. ca. 1 mm long).

Figures

FIGURE 24. Lasianthus candidus V.S.Dang, Naiki & Yahara (from V5877, VNM): A. Branch with flower buds, B. Close-up of young branch and leaves, C. Stipules, D. Abaxial leaf surfaces, E–I. Inflorescence showing side view calyx, buds and flowers (A, E, I: photos by Shuichiro Tagane).

FIGURE 25. Distribution maps of Lasianthus candidus subsp. candidus, L. candidus subsp. hoanglienensis, L. capitatus subsp. vietnamensis, L. chevalieri subsp. chevalieri, L. chevalieri subsp. gianglyensis and L. chii.