A technique is described whereby regular growth of roots is obtainable with good aeration. Decapitation at 0·5, 1, or 2 mm. behind the root-apex does not accelerate the growth of the stump. An obvious retardation of growth is recorded when 2 mm. of the root-tip is removed, a less conspicuous retardation, or no effect at all, is recorded when shorter parts are removed. The amount of retardation is affected by the extent to which the apical meristem is removed. The growth of stumps reheaded with their own tips is similar to that of unreheaded stumps.