1. A study was made of the comparative transpiration rates of leaves of rooted Eureka lemon, Marsh grapefruit, and Valencia orange cuttings. The rate was highest for the lemon, less for the grapefruit, and least for the orange. 2. It was found that 2 to 3.5 times as much water was transpired through the under as through the upper leaf surface. There was a difference, however, in the ratio of the water loss from the dorsal and ventral sides, lemon showing the highest and orange the lowest values. 3. The water loss from detached leaves confirms the results obtained with leaves of rooted cuttings.