Abstract
The grain pattern in wood and the pattern of orientation of ray splitting and uniting were studied in roots and root collar of Platanus acerifolia. In roots the interlocked-grain wood was observed as in the stem. An analysis of changes in xylem rays indicates that the cambial domain pattern exists and migrates upward there. In the root collar the grain in wood was straight although cambial domains were noted too. The domain pattern is characterized by relatively wide variations of the domain length and by pulsation: expanding some domains and reducing others so that it does not become manifest in the grain.