| Sumario: | This paper describes the origin and early histogenesis of the leaf in Coffea arabica L. cv. bourbon Choussy. As in most plants so far studied, periclinal divisions in the cells of the second tunica layer mark the first indication of leaf initiation. The activity of the apical initials ceases early in the development of the leaf, and thereon, all growth is due to the adaxial and marginal meristems as well as the expansion of the existing cells. The marginal and submarginal initials give origin to an 8-tier plate meristem, from which the leaf blade arises. Some theoretical considerations are given in the discussion to the problem of differentiation of leaf traces.
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