A and B plants

[Sam G]

The most striking difference between the Herbal A and Herbal B illustrations is the use of red in the coloring, which is abundant in A ("thin red lines" in branches and stems, and red "berries"/"seeds" and flowers) but basically absent in B (possible exception being f55r, though this looks like the work of the postulated "heavy painter" who modified the manuscript at a later date).

I think there's also a difference in the overall character or feel of the A and B illustrations too, though it is hard to describe. The B illustrations do appear a bit more "three-dimensional".