Microscopic Analysis of Anatomical and Taxonomic Characteristics in Some <scp> <i>Centaurea</i> </scp> Species

This study was carried out using light and scanning electron microscopy to examine in detail the anatomical and micromorphological characteristics of roots, stems, and leaves of six Centaurea taxa (two of which are endemic) to determine the characters that are important for the taxa studied. For anatomical investigations, transverse and superficial sections were taken from root, stem, and leaf organs and examined by light microscopy. For micromorphological assessments, dried leaf surfaces were analyzed via scanning electron microscopy (SEM). Several statistical methods were used for data analysis. A total of 38 characters were considered to determine the anatomical differences among the taxa. Anatomical analyses indicated that variations in the structure of sclerenchyma, phloem, and cortex parenchyma in root; epidermis, chlorenchyma, sclerenchyma, and phloem in stem; and upper epidermis, upper, and lower stomatal characteristics in leaf, including stomatal and epidermal cell density, were statistically significant among the taxa. SEM investigations revealed the presence of four types of trichomes and extrafloral nectaries (only C. carduiformis DC. subsp. carduiformis var. carduiformis) on the leaf surfaces.