Development of the shoot apex inSesamum indicum Linn, andEruca sativa Mill, was followed from the mature embryo to early reproductive stages. The shoot apex shows an age-related increase in size until the reproductive phase sets in. In both species, the epicotyl apex is flat with a single tunica layer covering a homogeneous corpus. InSesamum the 3-day old seedling apex shows the early stages in the establishment of cytohistological zonation in the corpus leading to well-established zonation in the dome-shaped 4-day old seedling apex. InEruca the maximal stage of the 3-day old seedling apex is a low dome and zonation in the corpus is well established in the 4-day old apex. Establishment of zonation seems to be related to the size of the apex in the first place and probably to the shape also as applied to particular species. The sequence of establishment of zones is, the peripheral zone first followed by the corpus mother cells and pith meristem zones almost simultaneously.