Viola (odorata or tricolor)

[rikforto]

Don't get me started on Viola taxonomy, it's a nightmare! 

However, regarding the VM plant, regardless of color, there are only 2 closely related species (disregarding subspecies) that look similar:
V. arvensis
V. tricolor

Potentially dumb question from the botanically challenged peanut gallery: Difficulties of the illustrations aside, how sensitive were people circa 1400 to this taxonomy? I understand the medievals could be quite sophisticated herbalists, but would they have carved up the space of plants this way?