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| Lasianthus sondangii Bao, Vuong & V.C.Nguyen, in Tran, V. C. Nguyen, Luong, Phan-Thi, H. T. Nguyen, Truong et Q. B. Nguyen, 2026. |
Abstract
Lasianthus sondangii, a new species from Lasianthus section Nudiflorae, is described from Khanh Hoa Province, Central Vietnam. It can be distinguished from other Lasianthus species in Vietnam and surrounding countries by having narrowly triangular stipules, spiciform inflorescences with two or three reduced cyme secondary axes, purple flowers, and clavate calyx lobes with revolute margins. A detailed description of the new species, color plates, distribution, habitat and preliminary conservation assessment are provided.
Keyword: Indochina, Khanh Hoa, Lasiantheae, plant conservation, plant diversity, sect. Nudiflorae
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| Lasianthus sondangii Bao, Vuong & V.C.Nguyen. A. A flowering and fruiting branch. B. Apical shoot showing young leaves and stipule. C. Inflorescence and infructescence. D. Infructescence (side view) E. Flowers buds (mature (left) and immature (right)). F. Open flower in different views (side view (left) and top view (right)). G. Corolla artificially cut open, showing hairs at the throat and stamens. H. Flower with the corolla removed to show the ovary, calyx, style, and stigma (left) and longitudinal section that shows the calyx lobes, and the ovule (right). I. Mature fruit (left) and the cross section of fruit shows pyrenes and albumen of seeds (right). Drawn by Phan Thi Thanh Nha from type QB137. |
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| Lasianthus sondangii Bao, Vuong & V.C.Nguyen. A. Habit and habitat. B. A flowering and fruiting branch. C. Apical shoot showing young leaves and stipule. D. Stipule. E. Leaves (adaxial surface (left) and abaxial surface (right)). F. Infructescence. G. Inflorescences. H. Inflorescence bearing open flowers. (A, B, E–H by Nguyen Van Canh; C, D by Nguyen Quoc Bao from type QB137). |
Lasianthus sondangii Bao, Vuong & V.C.Nguyen, sp. nov.
Diagnosis: The new species is distinct from other Lasianthus species in Vietnam and Indo-China by its spiciform, sympodial, reduced-cymose inflorescence; purple flowers (including calyx), calyx lobes obovate with revolute margins.
Thi Thuy Nhan Tran, Van Canh Nguyen, Van Dung Luong, Thanh Nha Phan-Thi, Hoa Thi Nguyen, Ba Vuong Truong and Quoc Bao Nguyen. 2026. Lasianthus sondangii (Rubiaceae, Lasianthus section Nudiflorae), A New Species with a unique spiciform inflorescence from Central Vietnam. Taiwania. 71(3); 488 - 494. DOI: 10.6165/tai.2026.71.488 [26 May 2026]