Abstract
In coniferous stems the rate of multiplication of fusiform initials in the vascular cambium by means of pseudotransverse division often fluctuates considerably around the circumference. In fluted stems the frequency of these divisions is appreciably higher and the ratio of survival of the newly formed initials relative to the rate of production lower in the depressions than in the adjoining convex portions of the perimeter. The probability that compression is a factor tending to accelerate the frequency of anticlinal division is indicated by the decided increase in rate in areas of the stem subjected to radial pressure. Higher frequencies of pseudotransverse division are accompanied by reduction in mean cell length of the cambial cells and hence of the derived wood elements.