I liked to proceed an ongoing, interesting discussion concerning Royal Ferns, Ophioglossum in wide sense, reported hybrids within and a newly published allo-tetraploid species found in SE Asia. You may find it at observation Observation 25993646 plus lesser part at Observation27673795
I liked to proceed this here at iNatForum, but no longer directly at observations, for that purpose i will copy gathered comments upon both observations to here, there are less contributions at latter observation. Don’t know if there was another, smarter chance to move discussions from observations directly to forum items.
1st. part of contributions to Observation 25993646:
The Paraphyly of Osmunda is Confirmed by Phylogenetic Analyses of Seven
Plastid Loci. Author(s): Jordan S. Metzgar, Judith E. Skog, Elizabeth A. Zimmer, and Kathleen M. Pryer. Source: Systematic Botany, 33(1):31-36.:
We also resolve subgeneric relationships within Osmunda s.s. and find that subg. Claytosmunda is strongly supported as sister to the rest of Osmunda.
H. Order Osmundales Link, Hort. Berol.: 445. 1833. Circumscription sensu Smith et al. (2006b). Order consists of one family. One family, six genera, and an estimated 18 species.
Family Osmundaceae Martinov, Tekhno‐Bot. Slovar.: 445. 1820. Circumscription sensu Smith et al. (2006b). Monophyletic (Yatabe et al., 1999; Schuettpelz & Pryer, 2007; Metzgar et al., 2008). Six genera and an estimated 18 species.
Claytosmunda (Y.Yatabe, N.Murak. & K.Iwats.) Metzgar & Rouhan, this classification (see below). Type: Claytosmunda claytoniana (L.) Metzgar & Rouhan (≡ Osmunda claytoniana L.). Circumscription equivalent to Osmunda subgenus Claytosmunda in Yatabe et al. (2005). Monotypic.
Erwin @erwin_pteridophilos commented:
@mwtreftig Malte you surely know this hybrid https://www.inaturalist.org/observations/1817991 would be declared as intergeneric by changing one parent to Claytosmunda, and intergeneric hybrids are the most exceptional, questioning separation of genera. http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=233500836
@erwin_pteridophilos you have a point!! I was not aware of this consequence of splitting the genus. You should send this to Eric Schüttpelz as coordinator of PPG-1
@erwin_pteridophilos …but see: it happens anyway… https://phys.org/news/2015-03-million-years-fern-genera-hybrid.html
@mwtreftig indeed Malte @crothfels & al.'s published intergeneric hybrid × Cystocarpium roskamianum is a most exceptional, inexpected one!
By that proving true the existence of rarely happening natural crossings of clearly, yet distant genera. Natural hybridization between genera that diverged from each other approximately 60 million years ago
Separating Claytosmunda from Osmunda raises the question how wide or narrow generic concepts shall be at all to be useful, and to achieve monophyletic units at best. So we got stronger or weaker subjective preferrences of unition or splitting in general, there is simply no calculable “right or wrong” value.
By the way, as commented upon https://www.inaturalist.org/flags/371238 there is the issue of appropriate intergeneric hybrid name. Christopher @choess mentioned it “would have to be something ghastly like Osmundclaytosmunda x ruggii”.
I proposed perhaps better sounding and useful combinations as “Hybridosmunda × ruggii” or “Mix(k)tosmunda × ruggii” (not sure if “×” needed to be placed in front of genushybrid?). Tyi @crothfels
Christopher @choess answered:
This is governed by the Code, Art. H.6.2: “The nothogeneric name of a bigeneric hybrid is a condensed formula in which the names adopted for the parental genera are combined into a single word, using the first part or the whole of one, the last part or the whole of the other (but not the whole of both) and, optionally, a connecting vowel.”
However, i do prefer personal freedom of people, hence do reject superfluous regulations, or to regard any likewise codes as ultimate laws anyone who liked to publish new combinations had to follow, as otherwise names were treated as “invalid”.
I won’t publish intergeneric hybrids, yet this article of nomenclatural code is nothing but suggestive to me and i surely don’t need judges for that purpose.
Sure, useful rules where essential, but not as forcing end in itself when leading to unspell- and readable miscreation of names.
End of part 1 of the whole conversation, the rest is going to follow.
Best regards to all, Erwin