Most interesting.
From a parallel universe... When I was trained on the animal code circa 1998, there was mention of FAX as publication (I'd have to look it up to see if it was accepted or not). At that time, I don't think there was anything about digital publication (e-mailing a pdf etc) as that was just coming into fashion, but Christian Thompson at USNM said it was to be included in the next code.
I recall an article on common usage too which would speak to the callosum/crossii issue if they were animals (although I do believe it exists in the plant code too). If a name is in "common usage" and "established" for an extended period, it may take priority over a previously published name, however, no means to get such a name integrated permanently was firmly in place. The name pretty much would require a champion to keep pushing to beat "real" priority.
Even more complicated, we have the current codes, but I guess we'd have to look back to the code in use at time of publication to know for sure in these cases, right, Guido? So if FAX is now excluded in the current code, but not in the code when tig/mark were described, it's up to interpretation of whether FAX is publication if not specifically mentioned.
You ar right that there is a difference between the animnal and plant code. And indeed at the time of markianum/tigrinum there was no mention of fax inhibition or no reference to digital publication.
The crossii/callosum issue was published in an extensive article in SIDA by me and the late Dr. Senghas of Heidelberg University.
Braem, G. J. & Senghas, K-H. (2000) - The intriguing case of Cypripedium crossii Morren, its priority over Cypripedium callosum Reichenbach fil. and its transfer to the genus Paphiopedilum Pfitzer – Sida, 19(2): 249-255.
There was and is is no provision for "common usage" or "established" in the ICBN.
11.3. For any taxon from family to genus inclusive, the correct name is the earliest legitimate one with the same rank, except in cases of limitation of priority by conservation (see Art. 14) or where Art. 11.7, 15, 19.4, 56, 57, or 59 apply. Thus the only article that is to be followed is:
11.3. For any taxon from family to genus inclusive, the correct name is the earliest legitimate one with the same rank, except in cases of limitation of priority by conservation (see Art. 14) or where Art. 11.7, 15, 19.4, 56, 57, or 59 apply.
(and 14, 11.7, and the other exceptions listed do not apply)
the earliest legitimate name for "callosum" is "crossii" and as those names were published at the same level (species) crossii has priority. That case is as clear as water.
The problem I have with the current code is that it includes man-made hybrids. I think that is wrong (and I believe to have heard Hooker fil. and Thiselton-Dyer turn around in their grave after thoes block-heads of the Botanical Committee did that.
And yes, one has to take the valid code at the time of publication. You can't apply the 2010 Code to a publication prior to 2010.