The corolla is purplish-violet.
The tube is between 5 and 7mm and the extended part of the calyx or corolla (aka limb) between 7 to 15mm across.
The calyx is divided between about half-way to almost to its base (as opposed to being divided to the base in
The calyx lobes are acute in both
Alkanet and in and
Garden Anchusa (but obtuse to rounded in
Yellow Alkanet - which has a yellow corolla)
Hybridizes with :
Yellow Alkanet (Anchusa ochroleuca) to produce Anchusa × baumgartenii which is intermediate in hairiness and in the tips of the calyx-lobe. The corolla is either pale blue or greyish-yellow. The calyx is divided at less than half-way to the base. It is only partially fertile. It also forms back-crosses which have mostly yellow corollas.
Some similarities to :
Garden Anchusa (Anchusa azurea) which have a bright-blue corolla which is the commonest Anchusa grown in gardens. It too is a neophyte and rather infrequently found on waster ground or rough ground and tips.