Do Herbal A and Herbal B correspond to differences in imagery?

[Anton]

I don’t know how to explain these observations about the Herbal section.

I guess these observations can be interpreted in a straightforward fashion. For the dividing line in the stem, it's just a stylistic difference. The A scribe (or the artist who worked together with the A scribe) had the habit of separating stems with a line. He was also in habit of colour annotations, while the B scribe was not.

The B scribe was short of red paint, as opposed to the A scribe.

The latter observation is important, because it shows that the scribes worked separately from one another, that is - not at the same location.