medullary

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

部发达，明显。

2.Blood production —The marrow, located within the medullary cavity of long bones and the interstices of cancellous bone, produces blood cells in a process called haematopoiesis.

造血-骨位于长骨腔和松质骨间隙内，骨通过造血作用产生血细胞。

3.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.

位于顶端分生组织中部，、皮层、以及叶肉这些基本组织均是由基本分生组织分化而成。根部分生组织也称为皮层原。