Abstract
A comparative study on the structure of vascular cambium of Betulaceous plants has revealed that the typical nonstoried cambium is composed of fusiform and ray initials in all plants examined. The size measurements of fusiform initials in tangential sections have revealed that the average length varies from 347. 6-659. 6μ m in the examined species, the maximum being in Alnus hirsuta and the minimum in Carpinus laxiflora. And then the length of fusiform initials depends on the length of the pseudotransverse end walls which undergo intrusive growth to varying extents in different species. In each species ray initials have their own size, magnitude, frequency of occurrence. The relative proportion of ray initials falls about 13. 4-37. 5%. Shrubby Corylus has lower proportion of ray initials than Alnus which possess wider trunk.
