NECTARY. A surface gland which secretes nectar (q.v.). The name is also applied to abor tive floral organs (see below). Neetaries are most common in the flowers of seed plants, hut are found also in regions remote from the flower (Fig. 1). Extra-floral nectaries are found on the leafstalks and at the base of the leaf-blade, upon stipules and other portions of the leaf-base, and more rarely upon the blade itself.
The forms of neetaries are very various. The secreting surface frequently covers a more or less pronounced swelling or cushion of tissue, which may develop on the base of the flower leaves, or on the axis of the flower between them. Some times a neetary stands in the place where in other related flowers well-formed and functional floral organs stand. This fact has led to the application of the term nectary to abortive floral organs even when they do not secrete nectar. Sometimes the nectar gland forms a continuous ring about the base of the pistil. in cases the nectar gland lines the concave surface of depressions in the floral organs or the floral axis. When these pits deepen they con stitute efficient receptacles for the secreted nectar•.
Thus. petals and sepals are often furnished with nectar glands on the inner side or at the base of the spur. and the whole cavity may become filled with their secretion. Nec tar glands sometimes line deep and narrow pits of small capacity, opening at the surface by a pore or cleft. from which the nec tar oozes. These passages may be branched, so that a complex gland is formed, such as is found in the pistils of some lilies (Fig. 2).
Nectar varies greatly in composition in different plants. The greater part of it is water, which is withdrawn from the gland Cells by the osmotic action of the sugar. ( See SECRETION.) In addition to sugars (glucose and saecharose)small amounts of iiroteids and various other carbon compounds give the peculiar odor and flavor to the nectar. Nectar is eaten by bees, wasps, butterflies. and other insects, which in their search for it arc utilized as unconscious carriers of pollen. See POLLINATION.