Begoniaparvibracteata, a new species in Begonia sect. Platycentrum (Begoniaceae) from Guangxi of China, based on morphological and molecular evidence.

The previously reported begonias in a limestone forest of Guangxi mainly belong to Begoniasect.Coelocentrum Irmscher. In this article, we described and illustrated a new species in sect. Platycentrum (Klotzsch) A.DC., Begoniaparvibracteata X.X.Feng, R.K.Li & Z.X.Liu, which was discovered in a karst forest of south-western Guangxi. The begonia shows high morphological similarity to B.subhowii S.H. Huang and B.psilophylla Irmscher, but differs from the latter two in its narrower oblique-ovate asymmetric leaf blade, 4 (occasionally 6) tepals of pistillate flower and smaller membranous inflorescence bracts. Molecular phylogenetic analysis, based on ITS sequence data, supports the new species as monophyletic and distinct from B.subhowii and B.psilophylla. Considering its narrow distribution and the disturbance of human activities, the conservation status of new taxon is evaluated as "Vulnerable" (VU B1, B2 ab (i, iv, v), D2) according to the IUCN Red List Categories and Criteria.

Begoniapseudoedulis, a new species in Begoniasect.Platycentrum (Begoniaceae) from southern Guangxi of China.

Begoniapseudoedulis, a new species in Begoniasect.Platycentrum (Klotzsch) A.DC. (Begoniaceae) from southern Guangxi of China, is here described and illustrated. It morphologically resembles B.edulis H.Lév. and B.dielsiana E.Pritz. ex Diels but differs easily by its hairy petioles and inflorescences, and red hispidulous flower tepals, ovary and capsules. The molecular phylogenetic analysis based on ITS supported that the new species was a monophyletic lineage, separating from both B.dielsiana and B.edulis. Due to its isolated distribution with several small populations, which are possibly disturbed by human activities, the species is considered as "Near Threatened" (NT) according to the IUCN Red List Categories and Criteria.