Thursday, August 21, 2025

[Botany • 2025] Decaneuropsis phongnhakebangensis • Notes on Decaneuropsis (Asteraceae: Vernonieae) in Vietnam, with a New Species, a New Name for Vernonia balansae, and Two New Combinations

 

Decaneuropsis phongnhakebangensis  Tagane & V.S.Dang, 

iin Tagane, V. S. Dang, Q. T. Pham, Yamamoto, Souladeth, Souvannakhoummane, Phengmala, Masuda, Fujiwara, Nguyen, N. K. Dang et H. T. Pham, 2025.

Abstract
A new species of Decaneuropsis (Asteraceae), Decaneuropsis phongnhakebangensis Tagane & V.S.Dang is described from Phong Nha-Ke Bang National Park in Quang Binh Province, North Central Region, Vietnam. A new name Decaneuropsis gagnepainii V.S.Dang & Tagane is proposed for the illegitimate name Vernonia balansae Gagnep. Two new combinations, D. bonapartei (Gagnep.) V.S.Dang & Tagane and D. macrachaenia (Gagnep.) V.S.Dang & Tagane, are proposed. A lectotype is designated for V. bonapartei. A key to species of Decaneuropsis in Vietnam is provided.

Keywords: Compositae, flora, lectotypification, limestone karst, new name, plant taxonomy, Vernonia

Decaneuropsis phongnhakebangensis.
A. Habit. B. Flowering branch. C. Abaxial leaf surface. D. Capitulum, top view. E. Capitulum, side view. F. Receptacle. G. Corolla opened out, showing stamens and style. H. Achenes with pappus. I. Achene.
Scale bars = 1 mm (F, I), 2 mm (G), 5 mm (H). Photos A–E taken by Shuichiro Tagane in the type locality on 10 December 2024.


Decaneuropsis phongnhakebangensis Tagane & V.S.Dang, sp. nov.
Nom. Vietnam: Bạch đầu phong nha kẻ bàng.
 
Similar to Decaneuropsis blanda (DC.) H.Rob. & Skvarla in the shape of leaves and capitula, but distinguished by its shallowly (4–)7–10-teethed leaf margin (vs. entire in D. blanda), eglandular stem, leaf blades, and achenes (vs. glandular), longer corolla 12.3 mm long (vs. 7–8 mm long), and longer and shallowly 11–12-ribbed achenes 5–5.8 mm long (vs. 10-ribed and 3–3.5 mm long) (Table 1).
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Shuichiro TAGANE, Van Son DANG, Quoc Trong PHAM, Takenori YAMAMOTO, Phetlasy SOULADETH, Keooudone SOUVANNAKHOUMMANE, Kajonesuk PHENGMALA, Riko MASUDA, Tao FUJIWARA, Quoc Hung NGUYEN, Ngoc Kien DANG and Hong Thai PHAM. 2025. Notes on Decaneuropsis (Vernonieae, Asteraceae) in Vietnam, with a New Species, a New Name for Vernonia balansae, and Two New Combinations.  Journal of Japanese Botany. 100(4); 287-294. DOI: doi.org/10.51033/jjapbot.ID0316  [August 20, 2025]