Trees of the genus Citrus can bloom all year round and are an abundant source of nectar for honey bees. Nectar production largely depends on nectary structure. The aim of this study was to investigate the structure of nectariferous tissues in hermaphrodite and functionally male flowers of the so-called Skierniewice lemon (Citrus limon cv. ‘Ponderosa’), which enjoys great popularity in Europe, using light microscopy as well as scanning and transmission electron microscopy. The nectary glands in both types of flowers differed in shape and size, but their structure and the pathways of nectar transport were similar. The intrastaminal nectary in the lemon flowers is composed of a massive ring-like located below the base of the ovary. Nectar is secreted through few modified stomata and probably through the microchannels in the cuticle. Numerous branches of vascular bundles, with phloem elements, penetrate the nectariferous tissue and reach the sub epidermal layers. The high content of endoplasmic reticulum, vesicles and Golgi bodies in the nectary cells indicates that the nectar is transferred by granulocrine secretion. The intercellular transport of nectar occurs using two ways: the symplast and apoplast pathway. The different regions of the nectary function asynchronously.

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