Sap
the nutrimental fluid which circulates in plants. As it rises in the stem it is of a watery nature and contains the various inorganic matters absorbed by the roots, also some sugar, dextrine, and other organic substances which it In has dissolved in its upward course. its passage to the leaves it becomes more and more altered from the state in which it was absorbed by the roots; but when it reaches the leaves it is still unfitted for the requirements of the plant, and is hence termed crude sap. Through the action of the light and air it undergoes important changes in the leaves and other green parts, and becomes adapted for the nourishment of the plant. In this state it is termed elaborated sap.
In dicotyledons this elaborated fluid descends through the internal bark and cambium layer toward the root, and is transmitted laterally inward by the medullary rays.