The Voynich Hercules

[Anton]

For the language implicitly underlying the mnemonics, I would in the first place consider Latin.

Entirely possible, but since the dog in Latin begins with letter C, I became disinterested in Latin at once  

Whatever the case may be, I think there are a few arguments against ordering by initial letter. One being that the plants tend to be thematically similar per page. Go through the section and you will notice: some pages are all roots, some are very green, others in between, others are very thick in symbolical imagery. The ordering appears to be by type, both botanically and in the extent of symbolism.

You probably did not understand what I meant, I did not mean that plants are grouped by letter, they are grouped by their belonging to the particular concoction. If components in recipes were to be grouped by letter, everyone could have become an apothecary. What is governed by letter is the choice of mnemonics. It's easier to remember three things starting with letter H than three things starting with different letters. But, as I said, that's rather a coincidence for this particular grouping, and the letter does not matter.