The investigation on anatomical properties of some Centaurea L. taxa (Asteraceae) natural distribution in turkey

Root, stem and leaf anatomy of six Centaurea L. (Asteraceae) taxa (C. aggregata subsp. aggregata Fisch & Mey, C. antitauri Hayek, C. balsamita Lam., C. cynarocephala Wagenitz, C. urvillei D. subsp. armata Wagenitz, C. urvillei D. subsp. hayekiana Wagenitz) belonging to five section (Acrolophus, Acrocentron, Cynaroides, Pseudopheopappus and Stizolophus) have been investigated by light microscope. The diagnostic anatomical features of these taxa have been described. The root well developed and showed secondary structure in all taxa. In C. aggregata subsp. aggregata, C. antitauri and C. balsamita, secondary xylem has more developed than secondary phloem. Secondary phloem and secondary xylem are the same size, and the number of parenchyma cells and their intensities in the secondary xylem is higher in C. cynarocephala, C. urvillei subsp. armata and C. urvillei subsp. hayekiana. Secretory ducts are schizogenous or lysigenous type in root. Large lysigenous type secretory cavities have been found in C. aggregata subsp. aggregata, C. balsamita, C. cynarocephala, C. urvillei subsp. armata ve C. urvillei subsp. hayekiana. In C. antitauri, there are schizogen and lisigen cavities in the secondary phloem and schizogen secretion gaps between medullary rays. The stem of the C. balsamita was primary structure. The other five taxon stems have secondary structure and showed Helianthus type secondary thickenning. Vascular bundles were open bicollateral type in all taxa. There was a vascular procambium was present in C. balsamita, there were vascular and intervascular cambium in other taxa. The number and size of vascular bundles varies between taxa. The number of vascular bundles is the highest in C. antitauri (73 vascular bundles), is the lowest in C. aggregata subsp. aggregata (22 vascular bundles). The length of small vascular bundle is the biggest in the stem of C. aggregata subsp. aggregata. The length and the width of major vascular bundle, width of minor vascular bundle and the trachea diameter is the biggest in the C. cynarocephala. The lowest trachea diameter was observed in C. urvillei subsp. hayekiana, the lowest vascular bundle size was observed in C. urvillei subsp. armata. In all taxa examined, leaves are isobilateral and amphystomatic type. Stomata are anomocytic type. Leaf stomate index is the highest in C. aggregata subsp. aggregata, but the lowest in C. cynarocephala. The data matrix consisting of 25 variables determined from the anatomical characteristics of the species were analyzed by Hierarchical Cluster Analysis, Factor Analysis and Principal Component Analysis methods. As a result of the analyzes, C. aggregata subsp. aggregata and C. balsamita were found to be similar in terms of their anatomical characteristics despite being in different sections. According to anatomical features of C. antitauri, C. cynarocephala, C. urvillei subsp. armata, C. urvillei subsp. hayekiana have been found to be different from the other two species.