Acropetal differentiation of the cambium layer continues as the primary root elongates.

形成向顶分化根伸长样在继续进行。

Interfascicular cambium A single layer of actively dividing cells between the vascular bundles in stems.

束间形成是于茎维管束间具有旺盛分裂能力细胞。

Bark The outermost tissue of the stem and roots in woody plants, on the outside of the phellogen (cork cambium).

木本植物中茎或根中木栓形成外方全部组织，称为树皮。