Lasianthus globularis V.S.Dang & Naiki (2021: 44)

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

27. Lasianthus globularis V.S.Dang & Naiki (2021: 44) — Fig. 49 (plate), Fig. 47 (map)

Type: — VIETNAM. Khanh Hoa Province, Hon Ba Nature Reserve, 1521 m elev., 20 July 2014, Tagane S., Kanemitsu H., Dang V.S., Tran H. with Hanh N., Loi X.N., Thach N.D., Dinh N., Hieu P.N.H. V1746 (holotype VNM! [ VNM00042891 ]; isotypes FU!, VNM! [ VNM00042892 , VNM00042893 ], the herbarium of Iriomote Station (Japan)) .

Specimens examined: — VIETNAM. Central: Khanh Hoa Province, Hon Ba Nature Reserve, 1521 m elev., 12°07’06.47’’N, 108°56’51.99’’E, in evergreen forests, 20 July 2014, Tagane S., Kanemitsu H., Dang V.S., Tran H. with Hanh N., Loi X.N., Thach N.D., Dinh N., Hieu P.N.H. V1746 ( FU, VNM, the herbarium of Iriomote Station (Japan)); in the same location, 919 m elev., 12°06’46.88’’N, 108°58’14.43’’E, in evergreen forests, 19 July 2014, Tagane S., Kanemitsu H., Dang V.S., Tran H. with Hanh N., Loi X.N., Thach N.D., Dinh N., Hieu P.N.H. V 1704, V1792 ( FU, VNM, the herbarium of Iriomote Station (Japan)); in the same location, 1502 m elev., 12°07’08.12’’N, 108°56’30.03’’E, in evergreen forests, 15 June 2019, Dang V.S., Dang 344 ( VNM!) .

Distribution: —Endemic to Vietnam (known only from the Hon Ba Nature Reserve, Khanh Hoa Province).

Habitat & Ecology: —In hill evergreen forests at 900–1550 m elev.

Phenology: —Flowering and fruiting from February to July.

Vernacular name: —Xú hưƠng cẫu.

Note: — Lasianthus globularis is morphologically related L. dalatensis Wernham (1921: 138) which is endemic to Vietnam in having the shape of leaves and inflorescences, but differing from this species by having fewer secondary veins (6–7 on each side of midrib vs. 7–9 on each side of midrib), smaller stipules (1–2 mm long vs. 5 mm long), and larger calyx (3–4 mm long vs. 1 mm long) and corolla tube (4–5 mm long vs. 4 mm long).

It is also similar to L. yaharae V.S.Dang, Tagane & H.Tran (2015: 352) which was described in 2015 from Hon Ba Nature Reserve, Southern Vietnam, but differs from the latter in having plants covered by smaller leaves (10–13 × 1.5–3 cm vs. 12–16 × 3–5 cm), more secondary veins (6–7 on each side of midrib vs. 4–5 on each side of midrib), smaller stipules (1–2 mm long vs. 2–3.5 mm long), smaller calyx lobes (0.4–0.6 mm long vs. 1–1.5 mm long), and fruits with 4 (vs. 5) pyrenes.

Figures

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

FIGURE 49. Lasianthus globularis V.S.Dang & Naiki (from V1746, VNM): A. Branch with young fruits, B. Close-up of young branch and leaves, C. Stipules, D. Abaxial leaf surfaces, E. Flower bud, F–H. Young fruits, I. Mature fruits, J. Seeds.