Morphological variation of reproductive traits in the annual section Polygonum taxa and its taxonomic significance
Keywords:
decision tree, dichotomous key, knotweed, perianth morphology, pericarp ornamentationAbstract
Paper description:
- Reproductive morphological characters are widely used in the taxonomy of section Polygonum, although their diagnostic value remains uncertain because of extensive overlap among taxa.
- This study analyzed quantitative and qualitative reproductive characters in seven annual taxa from 54 populations across the Balkan Peninsula and the Pannonian and Wallachian plains.
- The results revealed substantial overlap among several taxa and showed that most qualitative characters are unstable at the taxon level.
- The study highlights the limited resolving power of morphology alone and supports the need for integrative taxonomic approaches in section Polygonum.
Abstract: Reproductive traits are important taxonomic characters in section Polygonum. However, the taxonomic value of this character remains uncertain because of morphological variability and overlap among taxa. The goal of this research was to evaluate the discriminatory power of a comparative analysis of the quantitative and qualitative morphological characters of the bracts, perianth, and fruit in selected representatives of sect. Polygonum. The sample included seven taxa from 54 populations inhabiting the Balkan Peninsula and the Pannonian and Wallachian plains, and 23 quantitative and 9 qualitative morphological characters were analyzed. The results revealed a high degree of similarity between certain taxa, particularly P. aviculare and P. arenastrum, as well as P. arenarium subsp. arenarium and P. arenarium subsp. pulchellum. Almost all qualitative characters, with the exception of pericarp ornamentation, were found to be unstable at the taxon level, calling into question their previously emphasized taxonomic significance. Although newly analyzed quantitative characters provided additional information, they did not enable complete separation of the investigated taxa. Overall, the results indicate that morphology alone has limited resolving power within sect. Polygonum and highlight the need for an integrative taxonomic approach combining morphological, molecular, and ecological data.
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