Types of Cambium
On the basis of the arrangement of the Fusiform cells as seen in tangential section, cambium is divided into:
A) Storied/Stratified Cambium: The groups of ray initials may become taller either by the loss of fusiform initials located between two groups of ray initials, allowing them to fuse; or a fusiform initials can by transverse division, convert itself into a row of ray initials. All the structural elements that extend radially are produced via the ray initials.
In this kind the fusiform cells are arranged in tiers, or stories, i.e., the ends of cells'large tangential groups are aligned at similar levels of axis. If you view them tangentially the ends of cells in axially adjacent stories usually overlap only slightly creating a zigzag pattern.
B) Non-storied/Non stratified Cambium: In this type of cambium the ends of cambial fusiform cells typically overlap much more extensively and in a seemingly random manner. In Non-storied / Non stratified cambia there is no lateral alignment. In vesselless dicotyledons the fusiform initials may reach a maximum length of 6200 μm. Thus non storied initials are longer. They are also of more common occurrence.