Comparative Analysis of Section Calligonum and Pterococcus (Calligonum, Polygonaceae) Based on Fruit Morphology and Molecular Data

Comparative Analysis of Section Calligonum and Pterococcus (Calligonum, Polygonaceae) Based on Fruit Morphology and Molecular Data

Five Calligonum species with winged fruit were compared using morphological characters and trnL-F molecular data. Based on fruit traits cladistics analyses, two monophyletic clades were recognized, in support of previous division of species with winged fruits into two sections, sect. Calligonum and Pterococcus. In contrast, due to lack of adequate sequence variation, the relationship between them was not resolved by molecular data. The inter-specific variability within sect. Calligonum were significant for most of the morphological characters among section or between specie pairs. The morphological statistics indicated that the specie taxonomic status of C. colubrinum, C. squarrosum and C. klementzii should be retained. The high morphology diversity of sect. Calligonum in contrast with high genetic conservation and similar geographic range suggested that this section might have undergone rapid divergence. The rapid diversification could an adaptive evolution for the arid climate and desert habitat in Xinjiang from the Quaternary.