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the glands of a plant that secrete a sugary juice, or nectar. Nectaries are generally located in the interior of the floral cup, but they are sometimes situated outside of the flowers. The glands promote cross-pollination by attracting pollinators, primarily insects, to the flowers. (In the tropics, birds and, on rare occasions, bats serve as pollinators.)
Nectaries occur on the flower receptacle (for example, in the honeysuckle Lonicera iberica), on the interior or superior side of the sepals (in lindens), inside the spur (in nasturtiums), on the petals (in crowfeet), on the processes of the staminal connective (in violets), or at the base of the pistil (in buckwheat). In flowers that have an inferior ovary (plants of the families Umbelliferae, Dipsacaceae, and Compositae), the nectaries are located over the ovary and around the base of the styles. In some plants, flower organs (for example, the petals of meadow saffron) are converted into nectaries; in some rare cases (edelweiss and some acacias) a few flowers in the inflorescence develop into nectaries. Extra-floral nectaries are located on the basal parts of the cotyledons (in Ricinus), on the petioles (in mazzard cherry and plum), on the stipules (in vetch), on the bracts (in cotton), or on the leaflets of the involucres (in some species of Centaurea).
The cells of the tissue that elaborates nectar are for the most part small, thin-walled, and rich in protoplasm; often they constitute groups of special epidermal cells lacking cuticles (for example, the nectaries of apple blossoms). Nectar is usually secreted through the walls of the surface cells or, in some cases, through special stomata.