[Botany • 2025] Petrocodon parviflorus (Gesneriaceae) • A New Species identified by both morphological and molecular evidence from limestone caves in Guangxi, China

Petrocodon parviflorus F.Wen & K.Tan, 

in Liu, Tan, Chen, Bai, Xiong, He et Wen. 2025. 

 小冠石山苣苔 || DOI: doi.org/10.3897/phytokeys.260.153384

Abstract

Petrocodon parviflorus, a new species of Gesneriaceae, is a typically cave-dwelling species from the limestone region in Guangxi, China. Morphologically, this new species resembles P. lui, but can be readily distinguished by differences in corolla limb lobe shape, calyx lobe surface texture, pistil style length, and central staminode length. Molecular evidence supports its close phylogenetic relationship with P. lui despite their morphological distinctness. Based on the IUCN Red List Categories and Criteria, this species is assessed as Vulnerable (VU, D2).

Key words: ITS, limestone flora, molecular phylogeny, Petrocodon, taxonomy, trnL-F

Petrocodon parviflorus F.Wen & K.Tan, sp. nov.
 A. Habitat; B. Habit; C. Plant in the wild (Photographed by Chi Xiong)

 Petrocodon parviflorus F.Wen & K.Tan, sp. nov.
A. Adaxial leaf surface; B. Abaxial leaf surface; C. Bracts; D. Calyx lobes (the first three are adaxial surface and the last two are abaxial surface); E. Inflorescence; F. Face view of corolla; G. Flower in side view; H. Opening flower showing stamens and staminode; I. Stamens; J. Pistil; K. Stigma; L. Disc (Photographed by Rui-ning Liu).

 Petrocodon parviflorus F.Wen & K.Tan, sp. nov.

 

Diagnosis. The new species resembles P. lui in leaf blade shape, but can be easily distinguished from the latter by corolla limb lobes oval (vs. oblong, obovate to suborbicular), longer style length 10–11.5 mm long (vs. 4–6 mm long), longer central staminode 1–1.3 mm long (vs. 0.5–0.8 mm long), calyx lobes sparsely puberulent abaxially (vs. glabrous abaxially).

Etymology. The epithet ‘parviflorus’ reflects the relatively small flowers. The corolla is distinctly smaller compared to other species previously classified under the former Lagarosolen W.T.Wang, particularly L. lui Yan Liu & W.B.Xu (syn. Petrocodon lui).

Vernacular name. 小冠石山苣苔 

(Chinese pronunciation, Xiáo Guàn Shí Shān Jù Tái).

 Rui-Ning Liu, Ke Tan, Ping-Ya Chen, Xin-Xiang Bai, Chi Xiong, Song-Tao He and Fang Wen. 2025. Petrocodon parviflorus (Gesneriaceae), A New Species identified by both morphological and molecular evidence from limestone caves in Guangxi, China. PhytoKeys. 260: 201-212. DOI: doi.org/10.3897/phytokeys.260.153384