Saturday, March 11, 2023

[Botany • 2023] Hedyotis konhanungensis (Rubiaceae) • A New Species from the central highlands of Vietnam

Hedyotis konhanungensis  B.H. Quang, T.A. Le, K.S. Nguyen & Neupane, 

in Quang, Nguyen, Le, Linh, Nguyen, Ngo, Wu & Neupane, 2023. 
An điền Kon Hà Nừng  ||  DOI:  10.3897/phytokeys.221.95895

A new species of Hedyotis L. (Rubiaceae), Hedyotis konhanungensis B.H. Quang, T.A. Le, K.S. Nguyen & Neupane, is described and illustrated from the central highlands of Vietnam based on morphological and phylogenetic evidence. The new species belongs to the morphologically diverse tribe Spermacoceae (ca. 1000 species) of the family Rubiaceae, which is represented by 70–80 species in Vietnam. The phylogenetic analysis, based on four DNA regions (ITS, ETS, petD, rps 16), confirms the new species’ placement within the genus Hedyotis – one of the largest genera in the tribe, comprising ca. 180 species across Asia and the Pacific. Hedyotis konhanungensis is morphologically distinct from all southeastern Asian Hedyotis L. in its set of traits such as leaf type (shape and thickness), growth habit, and floral parts (color of inflorescence axis and the shape of calyx lobes). The new species shows similarities with Hedyotis shenzhenensis, H. shiuyingiae, and H. yangchunensis from China in its herbaceous habit, fleshy ovate leaf blades, and dark purple floral parts, but it is phylogenetically distinct and can be distinguished from them by the following combination of morphological traits: habit with slightly smaller stature (<25 cm), broadly ovate or deltoid stipules with cuspidate apex and entire margin, and ovate or nearly ovate calyx lobes.

Keywords: Gia Lai Province, Hedyotis-Oldenlandia complex, Indochina, phylogenetics, Spermacoceae, taxonomy

Hedyotis konhanungensis
A habitat B habit C stipule D adaxial and abaxial leaf surfaces E inflorescences top view F long-styled and short-styled flower G infructescence H fruiting branch.
Photos by Q.L. Nguyen and B.H. Photos by Quang, from Luan et al. LTA 531.

Hedyotis konhanungensis  B.H.Quang, T.A.Le, K.S.Nguyen & Neupane, sp. nov.
Diagnosis: Hedyotis konhanungensis is similar to H. shenzhenensis, H. shiuyingiae and H. yangchunensis from southeastern China (Guangdong and Hongkong) in the morphology of the leaf blades, floral bracts, dichasial cymes, and fruits, but differs from them by its broadly ovate or deltoid (vs. triangular or broadly triangular) stipules with entire (vs. hairy or lacerated) margins and cuspidate (vs. acute) apex, suborbicular or broadly oval (vs. subovate or ovate to lanceolate) lowest floral bracts, ovate or nearly oval (vs. triangular or subulate to lanceolate) persistent calyx lobes on fruits, and stamens in long-styled flowers inserted in lower ¼ or near the base (vs. at the middle or near the mouth) of the corolla tube (Table 1).

Etymology: This species is named after the “Kon Ha Nung Biosphere Reserve” where it was discovered.

Vernacular name: Vietnamese: An điền Kon Hà Nừng

 Bui Hong Quang, Khang Sinh Nguyen, Tuan Anh Le, Le Thi Mai Linh, Quoc Luan Nguyen, Duy Hoang Vu Ngo, Lei Wu and Suman Neupane. 2023. Hedyotis konhanungensis (Rubiaceae): A New Species from the central highlands of Vietnam. PhytoKeys. 221: 73-84. DOI:  10.3897/phytokeys.221.95895