Viola (odorata or tricolor)

[Bernd]

Ok, now it's getting ridiculous.
Who added the VM to the Wikipedia page of Viola rafinesquei? The entire paragraph is among the biggest nonsense I have ever seen on Wikipedia.

The Voynich Codex, also known as the Voynich manuscript, contains information that has been used to identify plants.

There is no evidence the VM contains information to identify plants. We cannot read the text. If anything, plants in the VM have been claimed to be identified. Most of these identifications are more than doubtful.

This 15th-century book contains an accurate drawing of Viola rafinesquii, with blue and white flowers, distinguishing it from Viola tricolor.

The VM flowers are either completely blue or blue and yellow and the coloration much better matches an average V. tricolor than [i]V. rafinesquei.
That aside, I'd like to remind you that T. tricolor is a widespread neophyte in North America, and I'd like to see you tell the plants apart without a chromosome count. These are highly polymorphic species aggregates that come in a huge variety of sizes and shapes and as I said many Violas are generally a nightmare to identify.

Well, here you go, give it a try!

The presence of this drawing suggests that Viola rafinesquii had medicinal uses for native populations in the early 15th century.

How exactly? Native Americans wrote the VM in Precolumbian early 15th century? Seriously?

All in all, I see no reason why V. rafinesquei should be a better match, unless you are trying to propose a New World origin of the VM.