[wavefunction]

Certainly. I agree with many of your excellent points. One other possibility is that this Manuscript copied from those earlier texts while 'adding' additional 'wholly new' creations. Or even that our knowledge of the bio-diversity of Central and South America is still lacking...

When this was still a curio with no apparent ties to any part of the world, I figured it was simply another 'esoteric knowledge system' using symbols and the structures of the information to convey that information without giving it away to the uninitiated. I wondered about the placement of leaves and vascular systems, colors used in combinations, the combinations of animals and plants and placements on the page. All the sorts of things esoteric scholars used to encipher their information in other works.

I think this final bit is what captivates the modern mind: we yearn to understand, even if the subject might turn out to be "meaningless" beyond a work of fantasy.