The stem leaves in Echium vulgare taper towards the stem; those in plantagineum are cordate (like the shape of the top of the heart on a playing card) at the base, or stem clasping. The flowers of vulgare are 12-15 mm long and have 4 stamens sticking out when seen from the side. The flowers of plantagineum are 20-30 mm long and have 2 stamens sticking out when seen from the side. Head on photos of Echium are of little use in identification..