As it has been established that the text content of the manuscript has nothing to do with the illustrations, the question arises as to the meaning of these graphics.
In my opinion, there is some evidence that the illustrations were not created by the authors of the text, but that these pages were acquired in this form, second-hand as it were.
Thus they were able to lend the book the impression of a work of natural science, as part of the encryption.
Apart from the pictures of plants, we find pages with depictions of concentric circles and rosettes.
I feel that these pages have the character of game boards or perhaps educational material. In this regard, it is interesting that at the centre of the pages f70v, 70r, 71v, 71r, 73r, 73v and 75r, labels appear in a non-Voynich script, called “Latin Marginalia”, whose meaning and language already was speculated extensively (it turned out, finally, that those are month names), but in relation to VM script did not obtain any significance.
I believe these markings to be strong evidence that the origin of the vellum is other than of Voynich authors.