Collateral or bicollateral vascular bundle, developmental pith and medullary ray are obvious.

髓发达，髓明显。

Ground meristem The central region of the apical meristem from which the ground tissues of pith, cortex, medullary rays, and mesophyll differentiate. In root meristem it is also called periblem.

位于顶组织的中，髓、皮层、髓及叶肉这些基本组织均是由基本组织化而成。根组织也称为皮层原。