It may develop by thickening of the secondary walls of parenchyma cells, or it may arise directly from meristematic cells. 它们可能由薄壁组织的细胞壁次生加厚而成，也可能直接来自于分生组织细胞。
The vascular cambium extends to form a complete ring of meristematic tissue around the stem, the separate vascular bundles being linked by interfascicular cambium. 维管形成层向两侧延伸直至形成一个茎内的分生组织环，各个维管束被束间形成层联系在一起。
