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In the period from September 2008 to July 2009 in the Grunwald district in the city of Poznań, Poland, a total of 609 localities of flowering English ivy were recorded, for which 769 plants were described. These plants were found in different localities, most of them euhemerobic. The biggest number of flowering specimens was recorded in home gardens. Support for climbing plants was mainly provided by trees and shrubs, including fruit trees – pear and apple trees. Among the other tree species, the biggest group comprises Scots pine, common birch, European larch and common locust. Other types of supports included fences, buildings and elements of small architecture. A very high number of specimens in the generative stage in the Grunwald district indicates considerable popularity and at the same time very good adaptation of ivy not only to the climatic conditions of the city of Poznań, but also to anthropogenic changes in the habitat.
In the present paper one of the biggest locality of generative specimens of ivy (Hedera helix L.) from Ryczeń near Leszno is described.
The structure of floral nectaries of ivy (Hedera helix) was investigated under light, scanning, and transmission electron microscopes. The nectar of ivy is located on top of the inferior ovary forming a distinct undulating disc between the base of petals and the style. The ivy nectary represents open and persistent nectaries. During consecutive days of anthesis, nectaries change their colour from green to brown. The secretory epidermis is covered with a thick, deeply striated cuticle, and nectar is released by nectarostomata. Epidermal cells exhibited plastids with plastoglobules and a few starch grains as well as vacuoles containing anthocyanins, the content of which increased during the successive days of anthesis and nectar secretion. Multi-layered glandular parenchyma and, underneath, subglandular tissue are located under the epidermis. The nectary was supplied by vascular bundles with phloem and xylem. Numerous chloroplasts were visible in the cytoplasm of the external layers of glandular parenchyma; they were either typical with small starch grains or untypical with circular arrangement of thylakoids. Amyloplasts containing storage starch grains and numerous small vacuoles were present in the cells of deeper layers of the nectar-bearing tissue. Druses, flocculent residue, myelin figures and spherical deposits of unknown origin were visible in the gland parenchyma vacuoles.
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