This study aims at analysing the chemical composition of the essential oils (E.O.) of four varieties of thyme (Thymus broussonetii, Thymus satureioides, Thymus zygis and Thymus vulgaris) and their comparison; through the principal components analysis (PCA) method; with new species of thyme (T. riatarum, lepobotrys T and T. munbyanus), previously studied by M. El Idrissi & all., 2012. As a matter of fact, this comparison is the identification or differentiation between species. Chromatographic analysis of thyme (E.O).has emerged different chemotypes. Thus, thymol, is both the chemotype T. zygis -Meknes 44.17% and T. vulgaris –Errachidia 35.87%. The chemotype T. brossenetii- Khémisset is carvone 46.70%, while that of Thymus satureoides from Agadir is the borneol 36.56%. (PCA) and hierarchical clustering (AHC) method shows a similarity of chémotye for T. vulgaris, T. leptobotrys and T. zygis, although the majority of compounds differ quantitatively. Same for the T. munbyanus, T. satureioides& T. riatarum which are chemotype “borneol
Keywords: Essential oils; differentiation; chemotype; ACP; GC / MS; thyme
