Leaves anatomy of family Cornaceae Bercht. et j. Presl representatives under conditional of Forest-Steppe of Ukraine

The objective – to compare of the leaves anatomy of the family Cornaceae Bercht. et J. Presl representetives from different geographic regions. The species Cornus mas L. and Swida sanguinea Opiz. are originated from Europe, Cornus sessilis Torr. and Cynoxylon florida (L.) Raf. – from North America, Cornus officinalis Sieb. et Zuss. and Cynoxylon japonica (DC) Nakai – from East Asia. We determined the similar anatomy of evaluated plants leaves. All species have dorsoventral type of leaf structure. The palisade parenchyma consists of 1–3 layers of cylindrical cells; the spongy parenchyma consists of oval cells, irregular shape cells, and intercellular spaces. In spite of similarity of the leaf anatomy all leaves are different in the quantitative parameters: size and amount of stomata, their density on the leaf surface, size of epidermal and parenchyma cells, leaf thickness, volume of intercellular area. The leaves of all discovered species except S. sanguinea are covered by flat, unicellular, T-shaped, 2-armed, symmetrical trichomes with short basal stalk. S. sanguinea has filiform, unicellular trichomes that placed along leaf veins. C. florida trichomes have the protruding calcium carbonate crystals. Trichome arms of other species usually have the micro-papillae on their surface. The leaf thick nesses of all discovered species are different. Asian species (C. officinalis and C. japonica) have the thickest leaf blades with 3-4 layers of mesophyll cells and large epidermal cells compared with European and American species. S. sanguinea is a species with width habitat and good adaptation properties: that plant is drought and frost resistant, and has the least leaf thickness among all studied species. All discovered species belong to the ecological group of xeromesophytes – the mesophyte plants those have xerophytic features. They have similar anatomy, what can be explained by their closely-related systematic location. The quantitative anatomy features of plants are consistent with their adaptation in introduction terms.