What is "guttation"

n. (context botany English) The exudation of drops of water from the leaves of some vascular plants as a result of root pressure.

Guttation is the exudation of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. Guttation is not to be confused with dew, which condenses from the atmosphere onto the plant surface.