]> http://purl.org/obo/owl/CL#CL_0000363 CL:0000363 These cells make up the axial system, also known as vertical or longitudinal system. plant_structure ISBN:0471245208 http://purl.org/obo/owl/ISBN#ISBN_0471245208 A vascular cell derived from the fusiform cambial initial and oriented with its longest diameter parallel with the main axis of stem or root. axial cell