Some morphological markers of Teucrium section Polium (Lamiaceae) from Morocco. Diagnostic values at different levels of integration

Abstract

The section polium of the genus Teucrium (Lamiaceae) is composed of groups of taxa that set problems of determination. This difficulty is the direct consequence, for a great number of taxa, of a lack of stable characters at the level of the species. This paper presents some morphological markers at different integration levels, the taxonomic value of which was tested in a biosystematic study we carried out, based on multiple characters.

Among these diagnostic characters we quote the proximal lobes and the trichomes of the throat of the corolla at the level of the subsection ; the leaves crenellated from the base, the shape of the calyx at the level of the group of species ; the simple and bifide trichomes at once, the presence of adventive roots at the level of polytypical species ; and some other characters at the level of non-dimensional species (or reduced-areas species) such as the plagiotropism of secondary and tertiary axes of inflorescence, the flower architecture, the presence more or less marked of proximal lobes and the seed surface.