Fruit anatomy of Tragopogon species (Asteraceae) and its taxonomic implications

This study presents an anatomical examination of fruits (cypselas) from 27 Tragopogon taxa, 14 of which are endemic to Türkiye. Mature outer cypselas, collected in the field or from herbarium specimens, were sectioned at the median region of the cypsela body, stained with safranin-fast green, and mounted in entellan to prepare permanent slides. The dendrogram derived from fruit anatomical data was generally congruent with the traditional classification; however, the examined taxa cannot be reliably identified solely on the basis of fruit anatomy, although these characters help to distinguish some closely related taxa. Principal component analysis based on 13 anatomical characters revealed that the widest and narrowest parts of the cypsela, including the primary ribs in the cross-section, and the pericarp width in the primary rib regions, were the most informative features for distinguishing the investigated Tragopogon taxa. Furthermore, discriminant analysis with leave-one-out cross-validation correctly classified most of the taxa into the four predefined fruit types, yielding an overall classification accuracy of 88.89%, suggesting that anatomical data generally support the informal groups initially defined by fruit characters and indicating substantial agreement between the two datasets.