Résumé
The wallflower Erysimum cheiri is a horticultural cruciferous growing as garden-escaped with a wide distribution in West and South Europe. In Algeria, it is locally found on the northern cliffs of the National Park of Gouraya (Kabylia). The aim of this study is to compare the populations of E. cheiri identified in Algeria with those found in Mediterranean France. To study the differences between both sites, a morphological and ecological analysis was undertaken on 6 populations growing in Algeria and France. Ecological communities where wallflower is growing in Algeria are dominated by indigenous plants with a significant proportion of endemic taxa, while in France the whole populations are growing in subruderal positions with the presence of other xenophytes and/or garden-escaped. Statistical analysis of the morphological traits revealed significant differences between the 2 sites following fruit discriminating variables ( stylus and seeds). Based on ecological and morphological divergences, we can conclude that the Algerian populations of wallflower are indigenous and represent a new endemic taxon named here E. cheiri subsp. inexpectans, distinguished from subspecies cheiri by a smaller and thinner fruit stylus and seeds that are often less numerous and always uniseriate within siliqua.