The genus Echium (Boraginaceae) in southern Africa

The genus Echium L. (Boraginaceae) comprises about 60 species, mainly from Macaronesia Europe, western Asia and North Africa. Two species E. plantagin eum L. and E. vulgare L. were introduced into southern Africa and have beco me naturalised. The species occur mainly as roadside weeds in the region. E chium is closely related to Lobostemon Lehm (incl. Echiostachys Levyns), en demic in the southwestern Cape region. Pollen morphology shows a remarkable similarity between these genera, even suggesting that they could be merged . However, other characters, such as bilobed styles (Echium) versus undivid ed ones (Lobostemon) and the presence of an annulus, composed of a minute c ollar or 5-10 minute hairy lobules, at the bottom of the corolla tube insid e (Echium), in contrast to hairs and/or scales at the base of the filaments (Lobostemon) contradict the pollen structure, and Echium and Lobostemon ar e therefore regarded as two separate genera. Significant taxonomic characte rs, an identification key, full descriptions, illustrations and distributio n maps of E. plantagineum and E. vulgare are given.