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[HermesRevived]

If the Voynich manuscript has been modelled upon the Lapidary of Alfonso,

Let's not forget that there are numerous manuscripts dedicated to the various properties of each degree of the zodiac. The Lapidary of Alfonso is well known because it is beautifully illustrated and used to belong to a king, but there are many other illustrated manuscripts and even more non-illustrated ones. 

Not all illustrated manuscripts use circular diagrams, but they show the same type of information.
You are not allowed to view links. Register or Login to view.  is a well-known example of the former, and You are not allowed to view links. Register or Login to view.  of the latter.

More important than these examples is that the theory behind this can be traced back many centuries and across late medieval Europe.
There are many ways how something similar could have ended up in the Voynich MS (if indeed this is the case). 
I find that idea very attractive, but of course we don't know yet.

That is certainly true; there are many such manuscripts - many medical lapidaries - and systems of astrology based on 360˚ were familiar. I think Antonio argues that there are iconographical similarities between the Voynich design and that of the Alfonso Lapidary that make the Alfonso Lapidary the only likely model. I am not sure of that, but if so then, I argue, the Voynich author is not likely to know the Lapidary directly, but only knows of it and its system. (Then I conjecture that someone in northern Italy could get a good account of the Alfonso system - and the Cordoban almanac - from Catalans teaching in Italian universities in the relevant period.)

But the Alfonso Lapidary may not be the specific model at all. The problem remains for other lapidaries: why isn't there 360 plants to match the 360 gemstones?