hydathode

noun

(Gr. ydatoô: to make watery; odos: road, way) An epidermal structure, a pore, specialized for secretion, or for exudation, of water, usually from a leaf. Like stomata, hydathodes are surrounded by two crescent-shaped cells but these, unlike guard cells, do not regulate the size of the aperture. Hydathodes are used by the plant to secrete water under conditions in which transpiration is inhibited; for example, when the atmosphere is very humid. This process of water loss is called guttation.