tThe anatomical and histochemical study of young and adult endocarps of Argania spinosa (sampled fromTindouf; Algeria) shows a general structure that is similar to that of majority of stone fruits. These samplesconsist of tissues that contain lignified and cellulosic cell walls. The majority of the tissues are composedof sclerenchyma cells; with very thick lignified cell walls and conducting tissues. Coniferyl lignins areabundant in the majority of the lignified tissues. However, the coniferyl lignins appear at the primaryxylem during lignification. Syringyl lignins are present in small quantities. The electron microscopy obser-vation of the sclerenchyma cell walls of the young endocarp shows polylamellate strates and, cellularmicrofibrils in arced patterns. This architecture is observed in the cell walls of the adult endocarp onlyafter the incubation of the tissue in methylamine. These configurations (arcs) are the result of a regularand complete rotation with a 180◦variation in the microfibril angle; the complete and symmetrical arcsshow a helicoidal mode of construction. The observation of the sclerenchyma cells revealed the capacityof helicoidal morphogenesis to adjust itself under the influence of topological constraints, such as thepresence of a large number of pit canals, which maintain symplastic transport.