After a short discussion on plant chimeras, the effects of the Na na alleles in Coffea arabica L. are presented and attention is called to the frequent appearance of somatic-mutations of these genes, which are very unstable under the influence of certain genetic backgrounds. The analysis of some of these somatic mutants is then presented in detail. The first case deals with a nana plant (na na), which produced a murta branch (Na na): the results of selfing and crossing seemed to indicate that at least the second germ layer, which produces the gametes, was affected by the mutation. Two murta plants (Na na) produced bourbon (Na Na.) branches, which proved to be of a chimerical nature, as their second germ layer was not affected by the mutation, maintaining its original genetic constitution (Na na). The exact structure of these chimerical branches has not been established, as it is not known yet how many germ layers exist in Coffea arabica L. and which of them are responsable for the morphology of the leaf. It is however concluded from the analysis of the above mentioned cases, that the second germ layer takes no essential part in determining leaf morphology. Combining the results of the 3 analysis, it is concluded that the first of the above mentioned plants must therefore have at least two modified germ layers.