Small lateral root origin. a First anticlinal cell division visible in the pericycle and endodermis. b A later stage in which two additional anticlinal divisions of the inner cell layer are visible. c Periclinal divisions inside the lateral root primordium giving rise to two inner cell layers. d At the later stage, almost all of the future lateral root cell layers are visible: the lateral root is ready to emerge. a–d Longitudinal sections of a radicle stained with naphthol blue black. e Transverse section of a radicle root through a lateral root showing the vascular connection between the primary root and the lateral root (illuminated under UV). en, endodermis; pe, pericycle; rc, future root cap; ep, epidermis. Scale bars (a–e) 25 μm.