Tuesday, July 5, 2016

[Botany • 2016] Begonia leipingensis • A New Compound-leaved Species (Sect. Coelocentrum, Begoniaceae) with Unique Petiolule Pattern from Guangxi of China


Begonia leipingensis D. K. Tian, L. H. Yang & C. Li (2n = 30), a new species in Begonia sect. Coelocentrum from the limestone area of Guangxi, China. B. leipingensisis is easily distinguished from any other compound-leaved species in Begonia by its large variation in petiolule number and its unique spirally-arranged petiolule pattern, which has never been seen in Begoniaceae before and rarely seen even in other angiosperm taxa. Besides having non-overlapping flowering periods, it is clearly different from B. fangii, the most morphologically similar species in the same section and with the same chromosome number. In addition to its unique petiolule pattern, B. leipingensis has longer abaxial wings, shorter internodes, and usually larger leaves, leaflets and habit. Molecular phylogenetic analysis showed that B. leipingensis formed an independent lineage belonging to Sect. Coelocentrum. Morphological and phylogenetic evidence strongly supports this species as a new taxon in Sect. Coelocentrum of Begonia. B. leipingensis was assessed to be critically endangered based on criterion outlined by IUCN Red List Categories and Criteria.

Keywords: China, Begonia, new species, morphology, endangered species, Eudicots

FIGURE 5. Habitat and morphology of Begonia leipingensis D. K. Tian, L. H. Yang & C. Li.
 A. Natural habitat; B. Small-medium individual with flowers. C. Inflorescence and flowers. D–F. Male flower (the frontal, side and back view). G. Androecium. H–I. Female flower (the frontal and side view). J–K. Young capsule (the frontal and side view). L. Cross-section of capsule with three parietal placentae. M. Dried mature capsule. N. Stipule (left: abaxial view, right: adaxial view). O. Bract (left: abaxial view, right: adaxial view). P. Large young leaf with eleven leaflets. Q. The widest leaflet ever seen in population.

Etymology:— This new species is named after the name of the town, Leiping, where it was discovered in Guangxi, southwest China.

 Distribution and Habitat.:— Only one population of this new species was discovered at Xinkang Village of Leiping Town, Daxin County, Guangxi, China (Fig. 7). The plants grow on moist rocks under the small trees and shrubs along shady pathsides on a limestone hill at 260–270 m elevation. 

Phenology:— Flowering August to October, fruiting September to December

Chun Li, Li-Hua Yang, Dai-Ke Tian, Yue Chen, Rui-Juan Wu and Nai-Feng Fu. 2016. Begonia leipingensis (Begoniaceae), A New Compound-leaved Species with Unique Petiolule Pattern from Guangxi of China. Phytotaxa. 244(1);