Abstract
In the vascular cambium of Platanus Z and S domains appear in the course of formation of the first annual ring. Their arrangement is connected with the division of the stem into nodes and internodes. In each node a domain of Z and of S type occurs. The longitudinal boundaries between them run along the middle leaf trace and on its opposite side, and the transverse boundaries lie in the nodes. Z-type domains are found on the right below the base of the nearest upper leaf, and S-type domains on the left. As the young cambium forms further rings, the size and shape of the domains changes.