Pelargonium L. genra (Fam. Geraniaceae) includes over 250 species, most of it native to southern Africa. Nowadays, four perennial species are cultivated in Romania as ornamental plants. Our aim was to establish the main characteristics and differences that occur between Pelargonium zonale, P. hispidum, P. grandiflorum, P. peltatum and P. radens. All in all, the quantitative differences (regarding the leaf-stalk, blade and trichomes) have a taxonomical value for all five species included in the research.
Materials and methods: The plant material was represented by fresh leaves harvested from 5 species of Pelargonium: P. peltatum (L.) Aiton, P. radens H.E. Moore, P. grandiflorum (Andrz.) Willd., P. hispidum. (anthesis phase) and preserved in ethanol 70%. Using a dissecting microscope, sections were made through leaf blade surface and cross sections of/ for leaf stalk and blade.
Results: The common characteristics of the leaf is the palmatilobate blade with long petiole. Although many studies regarded glandular trichomes from Pelargonium leaves, most of the leaf structures are still unknown. The most important for the quality and quantity of essential oil extracted from Pelargonium sp. are trichoms.