Lasianthus giganteus Naiki (2015: 165)

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

26. Lasianthus giganteus Naiki (2015: 165) — Fig. 48 (plate), Fig. 47 (map)

Type: — CAMBODIA. Kampot Province, Bokor National Park , 960 m elev., 17 October 2012, Tagane S., Fuse K., Choeun H.N. 4279 (holotype KYO!; isotypes Cam!, K!) .

Specimens examined: — VIETNAM. Central: Thua Thien Hue Province, Bach Ma National Park, 30 August 1941, J. E. Vidal 1052A (P); in the same location, 1285 m elev., 25 May 2015, Yahara T., Tagane S., Toyama H., Nguyen N., Nguyen C., Okabe N. V2722 & V2975 ( DLU, FU, KYO, the herbarium of Iriomote Station (Japan)); in the same location, 1193 m elev., 26 July 2019, Dang V.S. & Naiki A., Dang 408 ( VNM, the herbarium of Iriomote Station ( Japan)); Da Nang City, Ba Na Nui Chua Nature Reserve , 1489 m elev., 27 July 2019, Dang V.S. & Naiki A., Dang 422 ( VNM, the herbarium of Iriomote Station (Japan)); in the same location, 1489 m elev., February 2017, Tagane S., Nagamasu H., Nguyen V.N., Hoang T.B., Hoang T.S., Yang C.J., Kawakubo A. V 6948 ( DLU, FU, the herbarium of Iriomote Station ( Japan)) .

Distribution: —Indochina region ( Cambodia). In Vietnam, Lasianthus giganteus occurs in Da Nang and Thua Thien Hue.

Habitat & Ecology: —Growing under shade secondary forest or on the edge of submontane evergreen forests, at 1000–1500 m elev.

Phenology: —Flowering and fruiting from May to November.

Vernacular name: —Xú hưƠng đại.

Notes: — Lasianthus giganteus was described as new for the flora of Cambodia based on the specimen Tagane et al. 4279 ( KYO, K) which was collected from Bokor National Park of Kampot Province. This species is easily identified in the field in having elliptic to lanceolate leaves, oblique leaf base, secondary veins 16–17 on each side of midrib, bracts 15–18 mm long, and bracteoles narrowly lanceolate to linear, 5–18 mm long, and fruits conical, blue when ripe .

Figures

FIGURE 47. Distribution maps of Lasianthus foxworthyanus, L. giganteus, L. globularis and L. hatinhensis.

FIGURE 48. Lasianthus giganteus Naiki (from Dang 408, VNM and the herbarium of Iriomote Station (Japan)): A. Habit, B. Branch with flower buds, C. Close-up of expanding young leaves, D. Stipules, E. Abaxial leaf surfaces, F–I. Inflorescence showing side view bracts, flowering buds and flowers.