Lasianthus kontumensis V.S.Dang, Naiki & Tagane (2021: 38)

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

39. Lasianthus kontumensis V.S.Dang, Naiki & Tagane (2021: 38) — Fig. 64 (plate), Fig. 62 (map)

Type: — VIETNAM. Kon Tum Province, Ngoc Linh Nature Reserve , 1376 m elev., 12 February 2017, Tagane S., Nagamasu H., Nguyen V.N., Hoang T.B., Hoang T.S., Yang C.J., Kawakubo A. V 6404 (holotype VNM! [ VNM00042909 ]; isotypes DLU!, FU!, the herbarium of Iriomote Station ( Japan)) .

Specimens examined: — VIETNAM. Central: Kon Tum Province, Ngoc Linh Nature Reserve , 1376 m elev., 15˚10’07.04”N, 107˚45’43.04’’E, 12 February 2017, Tagane S., Nagamasu H., Nguyen V.N., Hoang T.B., Hoang T.S., Yang C.J., Kawakubo A. V 6404 ( DLU, FU, VNM, the herbarium of Iriomote Station ( Japan)) .

Distribution: —Endemic to Vietnam (known only from the Ngoc Linh Nature Reserve, Kon Tum Province).

Habitat & Ecology: —In hill evergreen forests at 1300–1400 m elev.

Phenology: —Flowering from February. Fruits not seen.

Vernacular name: —Xú hưƠng kon tum.

Notes: — Lasianthus kontumensis is similar to L. luciduc Blume in having glabrous or sparsely strigose on young parts, the shape of leaves and inflorescences, but differs from the latter in having more secondary veins (5–6 on each side of midrib vs. 3–4 on each side of midrib), shorter petioles (3–5 mm long vs. 5–8 mm long), larger stipules (1.5–2 mm long vs. 1 mm long), bracts 1–1.5 mm long (vs. absent) and larger calyx tubes (1–1.5 mm long vs. 1 mm long).

Figures

FIGURE 62. Distribution maps of Lasianthus khanhvinhensis, L. konchurangensis, L. kontumensis and L. lacduongensis.

FIGURE 64. Lasianthus kontumensis V.S.Dang, Naiki & Tagane (from V6404, VNM): A. Branch with flower buds, B. Close-up of young branch and leaves, C. Stipules, D. Abaxial leaf surfaces, E–G. Inflorescence showing side view flower buds, G–H. Calyx and flower (A, D–E, G–H: photos by Shuichiro Tagane).