Anatomy of Balkan Amphoricarpos Vis. (Cardueae, Asteraceae) taxa

Abstract

Anatomical analysis of root, rhizome, leaf, peduncle and inflorescences has been conducted on Balkan Amphoricarpos taxa, A. neumayerianus (Vis.) Greuter subsp. neumayerianus, A. neumayerianus subsp. murbeckii Bošnjak, A. autariatus Blečić & Mayer subsp. autariatus and A. autariatus subsp. bertisceus Blečić & Mayer using light microscopy (LM) and scanning electron microscopy (SEM), in order to examine the anatomical traits of this genus for the first time. All taxa show similar features. Young adventitious roots share a typical structure. Sclerenchyma fibers are present in the center of older root. On the rhizome cross sections, secondary tissues are noticed with wide parenchyma rays which interrupt a-well developed xylem. Rhizomes show eccentric growth. The leaf blade is amphistomatous, with dorsiventral structure. Crystal druses are found in leaf epidermal and mesophyll cells. The peduncle cross sections is characterized by more or less polygonal shape with medullary collateral vascular bundles arranged in a circle, and a few of them outside of the circle, toward to cortex region. Secretory canals are absent. Involucral bracts and paleae are characterised by the presence of multilayer sclerenchyma in the mesophyll. Inflorescence anatomy shows structures commonly described for Asteraceae members. Densely distributed vermiform (lanate) and glandular biseriate trichomes are present on the peduncle and on both leaf sides, but much more on the abaxial. Anatomical uniformity indicates very close relationships between examined taxa regarding conserve nature of the genome of the genus. Obtained characters contribute to the knowledge of the genus Amphoricarpos anatomy.