The flowers of Viola × wittrockiana Gams. emit odorous compounds. The glands found in the flowers, responsible for the production of essential oils, are most frequently distributed on the petals of the corolla. They include papillae – conical epidermal cells. The structure of the epidermis and the internal tissues of the petals of V. ×wittrockiana were examined using light, fluorescence and scanning electron microscopy. Papillae were found to occur in the epidermis on both sides of all the petals (spurred, lateral and upper), but they were much longer in the adaxial epidermis. Different-sized droplets of lipid nature, which are essential oils, were present in the papillae. They were also observed on the outer surface of the walls of these cells. Moreover, in the adaxial epidermis there were areas of flattened cells with a characteristic structure, being probably secretory glands. The present study shows that differently-structured cells of both the abaxial and adaxial epidermis participate in the release of odorous compounds by the flowers of V. ×wittrockiana. These different structures may produce varied scents in terms of their quality.

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