Voynich style herbs+text wrapping: BSB Cgm 728

[Jorge_Stolfi]

One hypothesis may be that the VM artist drew from a MS that already had color annotations and just took them on board, initially. ... If this hypothesis is correct, it would mean that the VM relied on a MS that was itself a copy with color annotations, which may or may not have been fully painted.

That is my guess too.

IIRC, those few "color keys" are all near the beginning of the Herbal section.  If that is indeed the case, it could mean that the VMS Scribe at first did not know what those letters were, but eventually figured it out, or had it explained to him .
All the best, --stolfi