Friday, January 27, 2023

[Botany • 2023] Commelina danxiaensis (Commelinaceae) • A New Species from Guangdong, China


 Commelina danxiaensis Q.Fan, Long Y.Wang & W.Guo, 

in Wang, Zhao, Chen, Huang, ... et Fan, 2023.
丹霞鸭跖草  ||  DOI: 10.3897/phytokeys.218.91199

Commelina danxiaensis (Commelinaceae), a remarkable new species from Mount Danxia, Guangdong Province, China, is described and illustrated. This species is similar to C. communis in inflorescences and flowers but readily distinguishable in its nearly erect stems, larger flowers, and different petal colouration.

Keywords: Commelinales, morphology, Mount Danxia, phylogeny, taxonomy

 Commelina danxiaensis Q.Fan, Long Y.Wang & W.Guo, sp. nov.
A habitat B involucral bract C inflorescence D flower E fertile, sterile stamens and pistil F fruit in transverse section G seed.

 Commelina danxiaensis Q.Fan, Long Y.Wang & W.Guo, sp. nov.
A habitat, growing on top of the Danxia landform B habit, plants ascending C–E leaf-blade, lanceolate to ovate-lanceolate F leaf-sheaths, with pubescence G–H flower I inflorescence J spathe K fruit in transverse section, 2 seeds per valve L seed.
 Scale bars: 1 cm (D, E, G, I, J); 3 mm (K, L).

 Commelina danxiaensis Q.Fan, Long Y.Wang & W.Guo, sp. nov.
Chinese name. 丹霞鸭跖草 [dān xiá yā zhǐ cǎo]
Diagnosis: Commelina danxiaensis is morphologically similar to C. communis due to their diffuse stems, lanceolate leaf-blades and approximate floral forms. However, it differs in its ascending stems (Fig. 4B), tomentose leaf-blades and sheaths (Fig. 4C–F), and sky-blue lateral petals with a white basal third (Fig. 4G).

Distribution and habitat: Commelina danxiaensis is only known from the type locality, Mount Danxia, Renhua County, Guangdong Province, China. Only two populations have been found, with several hundred individuals. It grows on dry mountaintops of the Danxia formation at elevations of 100–350 m.

 Long-Yuan Wang, Wan-Yi Zhao, Zai-Xiong Chen, Wei-Cheng Huang, Ming-Yan Ding, Jin-Chu Luo, Wen-Bo Liao, Wei Guo and Qiang Fan. 2023. Commelina danxiaensis (Commelinaceae), A New Species from Guangdong, China. PhytoKeys. 218: 117-126. DOI: 10.3897/phytokeys.218.91199