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

发达，线明显。

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.

位于顶端分的中，、皮、线以及叶肉这些基本均是由基本分分化而成。根分也称为皮原。