Up until recently Field Gromwell fell under the Anchusa genus, but taxonomists have decided in their wisdom to create the entirely new genus Buglossoides to accommodate this. Buglossoides used to also contain Purple Gromwell (which was called (Lithospermum purpurocaeruleum) but then called Buglossoides purpurocaerulea before being now called Aegonychon purpurocaeruleum within the new genus Aegonychon - which strangely is not in Stace 4).

The genus Lithospermum has not been abandoned altogether; it contains (in AD2020) just one species now: Common Gromwell, Lithospermum officinale. Wikipaedia shows several other plants (which do not [yet] occur in the UK) now residing in this new genus. So, three different genera for the 3 species of Gromwells which occur in the UK. Watch this space over the coming decades!

There is also a cultivar, Hidcote Comfrey Symphytum × hidcotense:
(Symphytum x hidcotense) which is also a triple hybrid; being the hybrid between Creeping Comfrey (Symphytum grandiflorum) and possibly Russian Comfrey (Symphytum × uplandicum) [with the latter being a hybrid between Common Comfrey (Symphytum officinale) and Rough Comfrey (Symphytum asperum)]

Both the genus Phacelia and the genus Nemophila are in the Hydrophyllaceae which is a sub-family of Boraginaceae. The taxonomy of the Boraginaceae is subject to much turmoil at the moment as taxonomists attempt to sort it all out.

Both the genus Phacelia and the genus Nemophila are in the Hydrophyllaceae which is a sub-family of Boraginaceae. The taxonomy of the Boraginaceae is subject to much turmoil at the moment as taxonomists attempt to sort it all out.