The micrib belonging to bicollateral bundle is well developed.The bundle sheath is composed of idioblasts.

主脉发达，有异细组成的维管束鞘，具双生韧皮部。

Plenty of laticiferous tubes were included in roots, stems and leaves.Intraxylary phloem formed around the pith.

髓的外围形成一环内生韧皮部，这些结构特征使罗布麻能更好的适应干旱、盐碱等恶劣环境。

Actinostele A rype of protostele in which the xylem is star shaped and the phloem lies between the points of the star.

原生中的一种类型。木质部是星形的，韧皮部星形之间。

These cells began to devise, then developed into aloin cells through enlargement of volume and vacuolization with the differentiation of metaphloem and metaxylem.

在后生韧皮部和木质部发育成熟过程中，这些细体积逐渐增大，并液泡化，发育成为大型薄壁细（芦荟素细），筛管外侧。