Morphological and anatomical study of the genus Hedera in Iran

Hedera is a genus of evergreen climbers distributed throughout Europe, North Africa, Macaronesia, and Asia. In this study, the morphological and anatomical structures of 11 populations from two species of Hedera (H. helix and H. pastuchovii) have been considered to evaluate the relationships in this genus. In total, 19 quantitative and eight qualitative morphological features were evaluated and measured. Ward’s dendrogram showed two main clusters. The first cluster is composed of populations of H. helix and the second cluster is composed of two subclusters containing populations of H. pastuchovii. Both species showed a bifacial leaf anatomical structure, so the mesophyll is differentiated into palisade and spongy tissues. Petiole cross sections showed rounded shape with wavy margin. Pedicel cross sections are similar in the general shape but the margins are different between two species. Both are rounded shape and the margin is quite wavy in H. helix and straight in H. pastuchovii. Number of vascular bundles of pedicel is different between two species. Two types of covering trichomes were identified including stellate trichomes in H. helix and scale-like trichomes in H. pastuchovii. Studied taxa were clearly separated by selected morphological and anatomical characters and these data provide additional evidence for species relationships between them.