Identification - help needed, please

I bought this plant earlier this year, and all the description it had was Mammillaria sp.Rog 095, N. of Escondida, NL. Herr Rogozinski's field list has (melispina??) by this entry.

According to Craig, M. melispina has yellow central spines, but no radial spines, and naked axils, though with some wool when young, and citron-yellow flowers. Fairly clearly this plant doesn't match that description.



The flowers look a bit like melanocentra, but it has two central spines, and the radial spines are not strong, as per the description for that species. It also has both some wool and a few bristles in the axil, again unlike that species. The older axils lose the wool, but not the few bristles.



I can't equate it to any obvious species, so clearly am missing something. Can anyone help me?

Hi Chris,

Just wondered with the two centrals, maybe m. melanocentra ssp. rubrograndis.

I'd be tempted to agree with you on that, if it weren't for the small flowers (rubrograndis are 4cm long, 4.5cm wide, whereas these are quite small; that the radial spine count is much less, and it isn't supposed to have bristles in the axils.

Mind you, I'm not sure just how "significant" these are, or how variable rubrograndis might be. So you could well be right.

This is my suggestion.....

OK, Maurillio, but I can't see a name! It looks like polyedra?

There are distinct similarities, though my plant doesn't look like is an offsetting species.

Yes, Mammillaria polyedra.
Today looking at my plants, i thought only the spination.
I would like to be useful to you but.....
You are correct.
Your plant is not offsetting and flowers are different.

Also, if the habitat info I have on this plant is right, it is a long way from M. polyhedra habitats.

Thanks anyway,

This is casoi FO 115 from oaxaca...

Nice plant, Maurillo, but not the one. M. casoi has few, if any radial spines, and flowers that are all pink. It also comes from Oaxaca, and about 1000km from Escondida, Nuevo Leon.

Its interesting how similar the two plants are, though casoi has much longer axillary bristles.

I'm assuming that my plant was correctly label led. It came from Rogozinski's collection, so I hope so.

ok.
To next game.

I think that it just has to be a form of M. melanocentra, whether rubrograndis or just plain melanocentra.

I suspect that this species is quite variable, and in places it probably intergrades between melanocentra and rubrograndis.

For now that is how I shall think about it. There isn't anything else in that area that it would be close to other than melanocentra. Its not a compressa or a magnimamma form, I think, nor a winterae, and apart from these, there are only heyderi and Formosa forms left to choose from, I think, and I doubt its one of these.