Intertaxon relationships
species
Phytoecia caerulescens (Scopoli, 1763)
Anchusa officinalis L. - Alkanet 
Cynoglossum officinale L. - Common Hound's-tongue
Echium italicum L. - Italian Bugloss
Echium vulgare L. - Viper's-bugloss
Inula conyzae (Griess.) Meikle - Ploughman's-spikenard
Lappula squarrosa (Retz.) Dumort. - Bur Forget-me-not
Lithospermum officinale L. - Common Gromwell
Rochelia disperma (L.f.) K. Koch
Salvia dumetorum Andrz. ex Besser