| 2. Vascular cambial cell |
1. Fusiform Initials
2. Ray Initials |
Between secondary xylem and secondary
phloem |
A. Procambium of fascicular regions
and from parenchyma of interfascicular regions in stems.
B. Procambium between xylem and phloem
and periclycle outside xylem in roots. |
-
Self perpetuating in tangential direction
-
Formation of secondary xylem in interior radial
direction
-
Formation of secondary phloem in exterior
radial direction
|
Three year old twigs of
Tilia
Pinus
|
| 3. Cork cambial cell (Phellogen) |
|
-
Between cork (phellem) and either phelloderm,
cortex, or phloem tissue
-
Beneath surfaces exposed by abscission of
leaves and stems and wounds
|
-
In stems, from either the epidermis, cortex,
or phloem parenchyma cells
-
In roots, from the pericycle
|
-
Self perpetuating in tangential direction
in some species; not in most
-
Formation of cork (phellem) in exterior radial
direction
-
Formation of phelloderm in interior radial
direction in some species
|
Three year old twigs of
Tilia
Pinus
Potato tuber |