The developmental anatomy of Dictamnus dasycarpus Turcz.roots was studied,using semi-sectioning,paraffin sectioning and maceration.The results show that the development of D.dasycarpus roots is characterized by four developmental stages,including promeristem stage,primary meristem stage,primary structure stage and secondary structure stage.The promeristem locates between the root cap and primary meristem,and clusters of cells from promeristem develop into the primary meristem which consists of protoepidermis,ground meristem and plerome.The protoepidermis develops into epidermal cells,the ground meristem differentiates into cortex,and the plerome develops into stele.The primary structure consists of epidermis,cortex and stele.And the outer cell walls of some epidermal cells develop into root hairs through outward growth.The oil cells and the casparian strip are also detected in cortex and endodermis,respectively.The primary xylem which is diarch or infrequent triarch is exarch.The center of the primary root is characterized by pith or not.The secondary structures derive from vascular cambium and cork cambium which differentiated from the cells in procambium and pericycle respectively.The secondary phloem is broad and contains 85% percentage of the root transverse section,the oil cells are also detected in the secondary phloem.The periderm is obviously thick.And abundant starch grains are existed in cortex and parenchyma cells of secondary xylem and phloem.