Öz In this stndy cambial activity and differentiation of Armeniaca vulgaris Lam. Which florvers early in spring were determined in a cross-sections taken from 1 year old shoots in seven days periods from February 1983 to .Tüne 1984. When these were compared witb tbe date of flowering and leaf development in tbe same years it was seen that phloem differentiation tock place just after tbe cambial reactivation togetber witb flowering. Xylem differentiation occurred after tbe completion of leaf development. The fact that flotvering occurred before tbe develop- meut of leaves, and tbe correspondence of this to tbe same time of phloem differentiation suggests that gibberellins might be playing an important role in this phenomenon.