Comparative study based on morphogenetic "in vitro" observations and biochemical analysis (phenolic compounds and peroxidases) have been conducted both on juvenile and mature clones of Sequoiadendron giganteum Buchholz. Meristem and microcutting investigations point out important intraclonal variations mainly due to physiological fluctuations of the stock plant whatever its age. For this reason maturation process and its vegetative reproduction consequences cannot be strickly characterized by steady biochemical or morphogenetic capacities references. Moreover further expiant evolution may be greatly influenced by "in vitro" culture conditions.