M. fertilis

I acquired a couple of plants under the name of Mammillaria fertilis. I read that they were a cristate form of Mammillaria backebergiana, and was happy enough with that. However over the last couple of years, both of them have sprouted a new offset, whic appears to be a more normal growth. I know this sometimes happens with cristate plants, so I was expecting the new heads to develop as Mammillaria backebergiana. However as you can see from the image taken today, the spination is nothing really like M. backebergiaia, looks much more like some form of M. magnimamma. Apologies about the bit a camera shake. It was cooold in the greenhouse!!

Any ideas??

Are you sure it's an offset and not a stray seedling?

Yes, I have a second plant and this also has a similar head like this. Not as long a spine on that one. I will check as they both need repotting and reply later today.

That is disconcerting and very interesting. Please, do keep us posted!

I repotted both of my plants of this and you can see (hopefully) how these "new" heads arise. They are now in 10cm pots, hopefully will feel better in the Spring after being in 7cm pots for many years. These came from the late Hugo de Cock in 2009.

That is really, really, strange. In the "original" you can clearly see the difference between radial and central spines, and there's no wool or bristles to be seen coming from the axils. Could it be some sort of chimaera?

I'm glad you are as stumped as me! I was checking through some of my plants and found these two behind another plant, and I had really forgotten about them. I think that Hugo probably acquired them when we visited the greenhouses of Helmut Rogozinski and then Wolfgang Plein. Maybe one of them will know, and if I get any more detail, I'll post it here. But yes, quite a mystery.

I found a photo of a plant amed as M. fertilis in Wolfgang Plein's collection. Herr Plein has sold his collection but I will ask him about this as he probably will know much more than I do.

It is hard to believe that these heads belong to the same plants as other around. Look is more as of M. compressa or M. magnimamma or something similar. Is this the way mutations appear spontaneously?

Can this be a seedling growing over the stem of other Mammillaria as we know some of them grow on tree stems sometimes?

Hi Agrippa,
I did wonder if somehow a seed had gone adrift, but when I repotted, the different head did appear to come out of the lower part f the main head body, quite low. I appeared to have grown some of its own roots as well. If it had been a stray seed, then I'd want to know why these two specific plants, when there were other plants around them, and also they were nowhere near where my magnimamm/compressa plants are situated, and the distance between is about 30 ft. I'm not aware of having had any birds in the greenhouse, nor any streams of ants. I can't really imagine what other seed disseminating insects there might be.
If and when I get some information from where they originally came from, I'll let you all know.

Chris, have you re-potted them before, since receiving them from Hugo? I would have thought you would have by now. So could it be a soil contaminated with rogue seed used at an earlier potting by you?
Maybe another possibility, with the odd heads originating so low down in the base of the main heads, could it be Plein used m. magnimmama as a grafting stock. Strange but not impossible.

Yes, I have reported them, it was 2009 when I had them from Hugo, and straight into 2 3/4 inch pots. Now in 4inch. So I think a stray seed of similar if not quite identical species, one into each pot is unlikely, and I never reuse potting compost, and always wash each pot in hot soapy water to re-use.

Chris,
Did you ever get any more info on these plants or a reply from Plein?

No, Wolfgang doesn't seem to be using email much these days.

OK Thanks Chris.