Is this expected?

[MrXeric]

Notocactus magnificus, which most experts agree is no more than a form (or variety) of Notocactus warasii.

I think you meant it the other way around: Eriocactus magnificus was published before Eriocactus warasii! In fact there exists the combination Notocactus magnificus var. warasii. https://caryophyllales.org/cactaceae/cd ... 28c51fab7a

(...) Hunt's morphological classification originally arose from trying to construct a simple classification for clueless Customs Officials to decide CITES issues instead of being a purely scientific one. Generally anything that looks remotely similar is lumped together, plus larger genera were easier to prohibit than having to individually distinguishing between many smaller ones! (...)

Hallo Dave, this is interesting information indeed. So here the Holy Burocracy sneaks into our nice classification system & wreaks havok.
...oh gosh...
N.

What Dave said may be true of some lumped genera in the past, but in this case there is valid evidence that lumping Parodia is not a bad idea.

There have been several molecular studies that hint at Parodia being monophyletic if lumped with the other genera (Notocactus, Eriocactus, Brasilicactus, etc). The most recent study being Nyffeler and Eggli's 2010 paper. Only 20 or species were sampled in that study (Parodia/Notocactus was not the focus of the study), but the results show that there is no clear cut way to divide these plants into only Parodia and Notocactus in such a way that the genetic relationships are conserved.

So the two options are to lump everything together into the oldest named genus (Parodia; the current popular approach), or to split everything into many smaller genera. Joël Lodé has taken the latter approach and has split these plants into Acanthocephala (a name that precedes Brasilicactus), Bolivicactus, Brasiliparodia, Eriocephala (a name that precedes Eriocactus), Notocactus, Parodia, and Wigginsia. At first I liked Lodé's splitting approach because it seemed to agree with morphological differences, but now I think he is jumping the gun, since there are 60 or so species currently accepted in the lumped Parodia, and only about a third of those have been sampled in molecular studies so far. A more complete study may validate the splitting, or may just show that there really is no internal separation that warrants splitting Parodia. If you're curious about Lodé's classification you can check out his website here.

[nachtkrabb]

What Dave said may be true of some lumped genera in the past, but in this case there is valid evidence that lumping Parodia is not a bad idea.

There have been several molecular studies that hint at Parodia being monophyletic if lumped with the other genera (Notocactus, Eriocactus, Brasilicactus, etc). (...)

Thank you very much, MrXeric. So its not only beaurocracy driving science, how comforting
And you also describe how some things change for the better, also very comforting.
N.

[DaveW]

The change from the past is DNA Sequencing which is supposed to give more accurate indications of relationships. Meaning which plants come from the same lines of ev0lution known as a monophyletic classification. In the past plants were largely classified on their morphology, meaning similar looking plants were lumped together. Whilst in most cases this worked occasionally DNA showed in the past plants from different ev0lutionary lines got "lumped" together, in the same genus, as in the case of Rebutia and Aylostera which have ev0lved to look the same through occupying similar habitats.

The policy these days is all plants within a genus are from the same evolutionary line = monophyletic classification. Unlike the past using morphology when sometimes genera were polyphyletic, meaning containing similar looking plants from different ev0lutionary lines.

However whether all the "bugs" have yet been worked out of DNA Sequencing is a matter of opinion since it still relies on interpretation by humans of the data. Also with any line of ev0lution as MrXeric says it is personal opinion as to where you divide it into different genera:-

"So the two options are to lump everything together into the oldest named genus (Parodia; the current popular approach), or to split everything into many smaller genera. Joël Lodé has taken the latter approach and has split these plants into Acanthocephala (a name that precedes Brasilicactus), Bolivicactus, Brasiliparodia, Eriocephala (a name that precedes Eriocactus), Notocactus, Parodia, and Wigginsia."

The choice therefore is yours whether you wish to "lump" all together under Parodia or "split" and retain many smaller genera. Neither classification is mandatory.

[nachtkrabb]

...classification might not be mandatory, but seems to be a good game.
N.