Starting with a "post scriptum", maybe this thread (and e.g. "Other succulents identification thread") could be pinned? I have seen similar "simple, yet common" questions threads are on many forums.
I acquired a few "random" young cacti and am trying to confirm their identity (I blame the person who posted about B&Q £2.50 cacti on the Facebook group):
Two-headed Ferocactus glaucescens:
Ferocactus glaucescens
Gymnocalycium pflanzii:
Gymnocalycium pflanzii
Matucana madisoniorum (I need to get some seeds, I clearly have a weak spot for them!):
esp wrote: ↑Fri Jan 29, 2021 12:35 pm
Your ideas look good.
Fero. glaucescens is (more or less) "inermis".
The Gymno may be saglionis rather than pflanzii?
As for:
MatDz wrote: ↑Fri Jan 29, 2021 11:33 am
Matucana madisoniorum (I need to get some seeds, I clearly have a weak spot for them!):
I got seeds of this from Koehres last year. Good germination. You may be half relieved to know they don't list them atm.
You might be right on the Gymno, they all look the same to me. Let's see if there are other votes for one of the other.
I indeed feel relieved I didn't miss them with the big Koehres order incoming!
atgamble wrote: ↑Fri Jan 29, 2021 9:05 pm
I bought a Mammillaria polythele 'Toluca' recently that looks fairly similar to your last photo. Appears to be a Mammillaria of some sort anyway.
Thanks, Google shows the one you mentioned as "inermis" (today I learned...), but the body shape is a match. I will look around Mammillarias.
atgamble wrote: ↑Fri Jan 29, 2021 9:05 pm
I bought a Mammillaria polythele 'Toluca' recently that looks fairly similar to your last photo. Appears to be a Mammillaria of some sort anyway.
Thanks, Google shows the one you mentioned as "inermis" (today I learned...), but the body shape is a match. I will look around Mammillarias.
Edit: It might simply be a Mammillaria polythele!
The botanical names seem to be contested for a great number of plants at the moment, I got a Sulcorebutia rauschii f. violacidermis the other week and when I've googled it to check cultivation requirements it seems that it is also known as Rebutia canigueralli. None of the websites really say which is the more up to date name though, which doesn't help!
There isn't such a thing as an up-to-date name. Naming is based on consideration of a whole bundle of macro and micro characters of a particular plant. The problem is that this information is then interpreted in different ways by different people and it is your choice as to which to follow. Sulcorebutias are a complete mess with a different name having been given to a population on each mountain. These names have then been lumped together by enthusiasts and botanists in various different ways. However the name that is best known to growers for your new acquisition is S. rauschii and if I was selling off spare cuttings, that is the name I would put on it.
The forma bit does not mean much, some people are just using that name to identify what is possibly a single clone of a variable species. It would really be better to use a cultivar name if one wants to identify it.
