Stem Anatomy of Some<i> Crepis</i> L. (Asteraceae) Taxa and Its Taxonomic Significance

In this study, the stem anatomy of nine Crepis (Asteraceae) taxa was described for the first time from T & uuml;rkiye. The anatomical data obtained were evaluated in terms of taxonomy with analysis of variance and principal components analysis. The stem mainly consists of a layer epidermis, parenchymatous cortex, collateral vascular bundles, and parenchymatous pith in all taxa examined. Glandular or non-glandular trichomes are found in the epidermal cells of the stem in some species examined. Even though all taxa examined have similar stem anatomy, quantitative traits such as the length or width of the anatomical characters significantly vary among the taxa. In particular, the xylem thickness considerably differs among the taxa studied, according to the results of analysis of variance. Besides, the xylem is thicker in caulescent species than in scapigerous taxa. According to the results of the principal components analysis, the xylem thickness and the epidermis cell length explain most of the total variation with about 82% value among the studied taxa. These results show that xylem thickness and epidermis cell length have a high taxonomic value.