Lasianthus chevarieli subsp. gianglyensis V.S.Dang & Naiki (2021: 56)

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

11.2. Lasianthus chevarieli subsp. gianglyensis V.S.Dang & Naiki (2021: 56) — Fig. 29 (plate), Fig. 25 (map)

Type: — VIETNAM. Lam Dong Province, Bidoup Nui Ba National Park, 1490 m elev., 19 February 2014, Toyama H., Tagane S., Dang V.S., Nagamasu H., Naiki A., Tran H., Yang C.J. with Ngoc N.V., Cuong N.Q., Hieu H.N.P., Loi X.N. V1823 (holotype VNM! [ VNM00042878 ]; isotypes FU!, VNM! [ VNM00042879 , VNM00042880 ], the herbarium of Iriomote Station (Japan).

Specimens examined: — VIETNAM. Central: Lam Dong Province, Bidoup Nui Ba National Park , 1490 m elev., 12°10’26.91’’N, 108°41’53.94’’E, in evergreen forests, 19 February 2014 , Toyama H., Tagane S., Dang V.S., Nagamasu H., Naiki A., Tran H., Yang C.J. with Ngoc N.V., Cuong N.Q., Hieu H.N.P., Loi X.N. V1823 ( FU, VNM) .

Distribution: —Endemic to Vietnam (known only from the Bidoup Nui Ba National Park, Lam Dong Province).

Habitat & Ecology: —In evergreen forests at 1300–1500 m elev.

Phenology: —Flowering and fruiting from February to June.

Vernacular name: —Xú hưƠng giang ly.

Notes: — Lasianthus chevalieri subsp. gianglyensis is similar to L. chevalieri subsp. chevalieri based on leaf and inflorescences shapes, but differs from the latter in having fewer secondary veins (7–9 on each side of midrib vs. 11 on each side of midrib), shorter petioles (5–8 mm long vs. 10–15 mm long), bracts 1.5–2.5 mm long (vs. inconspicuous), smaller corolla (11–12 mm long vs. 12–13 mm long for tubes, 4–5 mm long vs. 7–8 mm long for lobes) and yellowishwhite (vs. orange) when ripe.

Figures

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.

FIGURE 29. Lasianthus chevarieli subsp. gianglyensis V.S.Dang & Naiki (from V1823, VNM): A. Branch, B. Close-up of young branch and leaves, C. Stipules, D. Abaxial leaf surfaces; E–F. Inflorescence showing lateral view calyxes, buds and flower, H–I. Fruits, J. Seeds.