Thursday, June 18, 2026

[Botany • 2026] Argostemma baotingense (Rubiaceae) • A New Species from Hainan Island, South China

 

Argostemma baotingense S.P.Dong & H.B.Yang, 

 in Dong, Yuan, Wang et Yang, 2026. 

Abstract
Argostemma baotingense, a new species of Rubiaceae from Hainan Island, southern China, is described. This new species resembles A. bachmaense but can be distinguished by its suberect or creeping stem, linear leaves with a greenish-white abaxial surface, white and glabrous inflorescence, and glabrous calyx. An identification key and photographs of the nine Argostemma species in China are provided.

Key words: Argostemma, new species, taxonomy

Argostemma baotingense.
A. Plant in natural habitat; B. Flowering plant; C. Flowers; D. Calyx; E. Leafy branch, adaxial view; F. Leafy branch, abaxial view; G. Leaves, adaxial view; H. Leaves, abaxial view; I, J. A node with opposite leaves and stipules; K. Flower, apical view; L. Flower, bottom view; M, N. Inflorescence; O. Androecium; P. Pistil.

Argostemma baotingense S.P.Dong & H.B.Yang, sp. nov.

Diagnosis. The new species is morphologically similar to A. bachmaense T.V.Do but differs by the suberect or creeping stem (vs. erect), the linear leaves (vs. oblanceolate to spatulate), glabrous inflorescence (vs. pubescent), glabrous calyx (vs. pubescent). A detailed morphological comparison between the two species is provided in Table 1. Photographs of seven Argostemma species in China have been provided (Fig. 2). A key to all the nine species of Argostemma in China is also provided at the end of the text.


Shu-Peng Dong, Lang-Xing Yuan, Qing-Long Wang and Hu-Biao Yang. 2026. Argostemma baotingense (Rubiaceae), A New Species from Hainan Island, South China. PhytoKeys. 276: 253-260. DOI: doi.org/10.3897/phytokeys.276.195404   [18 Jun 2026]