Vascular cambium in 16 species of Salicaceae is nonstoried in all of them and is made up of fusiform and ray initials. The growth of cambial girth occurred by pseudotransverse division of fusiform initials and subsequent apical intrusive growth of daughter initials. The measurements of fusiform initials in tangential sections have revealed that the average length varies from 252.2-437.1㎛ in investigated species, with the maximum being in Populus euramericana and the minimum in Salix purprea var. multinervis. The length of fusiform initials depends on the length of the tapering end wall, therefore, the longer the length of the tapering end wall, the longer the length of fusiform initials. Ray initials have their own size, magnitude, and frequency of occurrence in each species. The relative proportion of ray initials fall about 15.0-24.5% in Salicaceae. Shrubby species of Salix have a lower ratio of ray initials than the species which possess wider trunks. New ray initials are originated from cut off the side or the end of fusiform initials and central partition of a fusiform initials.