Most certain plant ID's?

[MarcoP]

I wonder about the relations between these lists though. It seems that Th. Petersen, ELV and the Finnish biologist often agree where Sherwood has a different ID altogether. Does this mean that the first three partially influenced each other? Or that Sherwood had deviant identifications? Both scenarios have implications.

This seems difficult to answer. Rene says that "Ethel Voynich ("ELV") appears to have used Th.Petersen's lists and other sources to create her own list of tentative identifications". I don't know to which extent the Finnish biologist and Sherwood made use of the work of others. My impression is that the biologist worked from scratch on the basis of his professional knowledge.

It's been edited, with reference to Marco's post. I reduced the number of bolded ID's to the three superstars viola, ricinus and water lily.

Thank you, Koen. I think these three really stand out having a rather solid "historical" agreement. It's interesting that the Water Lily is in the short list even if the flower is closer to Lilium than Nymphaea (long pistil, six petals, curved outward, with crenated margins): I guess this means that agreement does not depend on a perfect match but on something more complex.

Let me know if anything else deserves to be bolded. (My personal favorite remains polygonum for You are not allowed to view links. Register or Login to view. - there was great agreement on the forum and it is found in some of the old lists).

It seems difficult to define a method to accept or reject candidates. Since this is based on agreement, maybe some kind of quantitative voting would be the way to go.
A possible addition could be 2r: the Finnish biologist says nothing, but the other three point out Cyanus (Cornflower, Centaurea Cyanus) or Knapweed (Centaurea Diffusa). If we limit ourselves to the genus (Centaurea) instead of a specific species (knapweed), maybe we can add this illustration to the list?

About f21r, this is the extended comment by the Finnish biologist from Stephen's site (italics mine):

The image 21r is a promising one in the sense that the artist has in my opinion certainly seen the plant when painting the image. It is so trustworthy and lively illustrated to represent a flat creeping plant, seen from above, radiating from a central root to all directions, which has been dug up - probably with a sharp tool - from a courtyard, roadside or similar hard, dryish site.

The plant seems to have modest tongue-formed leaves and modest more yellowish flowers in tight clusters. Unfortunately, the artist has not looked at the flowers more closely.

The problem is that there are so many unrelated plants which inhabit this niche and may have similar forms and rudimentary structures.

Without a systematic search, my first and best starting guess is some Herniaria species, since it is very similar indeed. The flower clusters are just like that, including te yellowish tone. It has been believed to cure hernia.

Secondary choices include Polygonum aviculare, Suaeda species and probably many mediterranean genera (Polycarpon, Parietaria etc.) which I am not so familiar with.

Polygonum Aviculare is confirmed as a candidate, but there are many unrelated plants that look similar to each other and to the illustration: from a biologist's point of view, there is no way to be sure about this id.