All procambial strands in six contiguous nodes below the tassel primordium of a young maize plant were traced from serial transections to reveal the pattern of vascular development. Each node consists of a disk of insertion and it's subtended leaf primordium. Within each disk of insertion, concentric, successive waves of isolated procambial strands are generated by a peripheral primary thickening meristem. These discrete traces become linked into sympodial leaf traces by merging with procambial traces from the subtended leaf primordia and with procambia of adjacent waves of their own and of adjacent disks of insertion. Median leaf traces, major lateral leaf traces, bud traces and intermediate leaf traces penetrate the disks of insertion to respectively decreasing depths. In addition, some procambia in the successive waves within a disk of insertion persist with blind ends. The nodal plexus arises as ground parenchyma adjacent to these blind endings dedifferentiates and forms horizontal procambial strands.

Key words: anatomy, development, node, procambium, Zea