The achene structures of Tragopogon L. (Asteraceae) taxa distributed in Turkey

In this study, the fruit (achene) structure of all Tragopogon L. taxa distributed in Turkey were examined based on 23 anatomical characters and evaluated numerically. Firstly, the selected achenes pre-treated in boiled water, embedded in paraffin and then cross-sections were taken by rotary microtome and stained by double staining method. Light microscopy observations show that epidermal ornaments were present in the intermediate rip region of T. oligolepis and main and intermediate rip regions of the rest examined taxa. It was determined that the exocarp is a monolayer and the mesocarp together with endocarp consists of multi-row parenchymatic and sclerenchymatic (mechanical tissue) cells. However, the thinnest pericarp in the main rip region was found in the T. graminifolius (91.77µm) and the thickest in T. pterocarpus (1405.73µm). The thinnest mechanical tissue in the main rib region was found in T. graminifolius (37,73 µm), the thickest in T. artvinensis (102,844 µm), thinnest parenchymatic tissue in the main rib region was found in T. graminifolius (43,24 µm), and thickest in T. pterocarpus (1277,16 µm). Air cavities were observed in the main rip regions of T. oligolepis and in intermediate rip regions of the rest examined taxa. Although the achene anatomical properties in general are very similar to each other, numerical analysis shows that achene diameter, thickness of pericarp and parenchymatical tissue are among the most valuable traits in delimiting the examined taxa.