Zonation in the shoot apex ofMatthiola incana was studied histochemically from the mature embryo to flowering. The plumular apex of the mature embryo shows a single-layered tunica covering a homogeneous mass of cells. The first evidence of zonation is seen in the shoot apex of the 2-day old seedling. Zonation is well established on the fourth day after seed wetting with a single-layered tunica covering a lightly stained central mother cell zone, a subjacent pith meristem and a densely stained peripheral zone. In the transitional apex zonation is less marked and there is increased stratification. At 6-weeks, the apex changes into the indeterminate inflorescence apex showing acropetally developing floral primordia. The axially located cells of the inflorescence apex are lightly stained. The histological and histochemical data indicate that zonation resembling that in the vegetative apex is retained to a lesser degree in the inflorescence apex as well.