n. (Gr. hydatos, of water; hodos, way) an epidermal structure specialized for secretion, or for exudation, of water.

Hydathodes, often found at the end of vascular bundles, are other derivatives of stomatal complexes. Their guard cells cannot be closed, unlike those in normal stomatal complexes. Water secretion by the hydathodes is called guttation; salts, sugars, and organic compounds dissolved in the guttation water crystalize on evaporation, forming a white powdery substance.