Anatomy and evolution in MacaronesianEchium (Boraginaceae)

The endemic Macaronesian members of the genusEchium (Boraginaceae) were examined anatomically to elucidate their relationships. Vessel length to breadth ratio was used as the initial guide to the relative primitive or derived nature of each taxon. Together with other features (e.g. trichome structure) it was possible to establish the phylogenetic pathways within this recently evolved relict group (Fig. 1).