Analysis of the productivity, germination and karyograms of new populations of P. albicans in Tunisia clearly confirms that germination strategies are correlated with an increasing aridity gradient and hexaploid or tetraploid and diploid cytotypes. Germination is synchronous for the seeds of the hexaploid populations in a semi-arid bioclimate with cool or temperate winters in the north and in the hills of the Dorsale region of Tunisia as in the hills of northern Morocco. The germination of tetraploids and diploids in a semi-arid or Saharan bioclimate with mild or cool winters in central and southern Tunisia, as in southern Morocco, takes place in successive waves. These remain true-to-type for several years before losing viability. In contrast, seeds from experimental cultivated plants, at least under the conditions used, lost their adaptation to the original biotope and germinated actively as soon as they were placed in favourable conditions. These results might form proof of the impact of the ecological conditions encountered by the seeds during maturation on their future germination potential.The distribution of chemical compounds confirmed the distinction between diploids and tetraploids in arid zones on the one hand and hexaploids in moist regions on the other. Nevertheless, the disappearance of poliumoside in experimental vegetative specimens, whatever their robustness, remains unexplained.