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

髓部发达，髓射线明显。

ResultsThe root of Tylophora atrolliculata Metc. had amphicribral vascular bundle, however steme had bicollateral vascular bundle.

方法利用显微镜观察其根、茎的横切面结构组织与根粉末特征。