Mammillaria magnimamma

I find it hard to correctly identify plants of this species, mostly because the series to which they belong is not one I am particularly fond of. That said, I regularly buy in flower shops and supermarkets the odd plant that impresses me because of its spines, and when they grow they conform to my general idea of that species. My question is: would you call the following plants M. magnimamma? If not, which one and why not (if it's not too much to ask for...)? Thank you.

1


2


3


4 (from seeds sent by a friend)


5 (this came mixed in a seed pack to which it shouldn't belong...)

In my humble opinion they are all magnimamma, and really Beautiful plants to boot!

Thank you, Thord.

The original description makes it clear.
3-7 spines bending towards the body, NO CENTRALS!
This rules out 2 to 5.
In my opinion, 2, 4 and 5 are Mam.centralifera, number 3, the one with offsets is somthing else?
The Reppenhagen books should be reprinted!, and everyone should have a copy.
Here is a picture of my Mam.magnimamma:

From left to right and top to bottom:
Rep1170,PN76,SB40,HO357,ML288,PN? Colon-Zamora,Hid.,PN151PN85 and PN178.
All without centrals!

Thank you, Walter. That was the kind of answer I was looking for.

And may I say, beautiful plants!

It can sometimes be difficult to be sure if what looks like a central spine is really a central, or just a stronger radial, pushed a little more towards the centre.
I believe that one of the distinguishing features, apart from the number of spines, between M. magnimamma and M. compressa, is the presence of bristles as well as wool in the axils of M. compressa. M. compressa ssp. centralifera (or M. centralifera if you like) is very recognisable because of the 1 or sometimes 2 central spines, which can curve downwards, which if only 1 then can be mistaken for M. magnimamma.
Walter shows very typical M. magnimamma, I think all the PN and SB ones are from Hidalgo. Elsewhere forms vary somewhat, and a number of older and not well described names have been revived. That isn't a problem, as taxonomists disagree on whether to use a species name for what others would call a species group - i.e. a group of species closely related.
This is why it is always best to know where the plant comes from, I believe.
However, to understand those plants which are closely related, the Reppenhagen books are very useful indeed. They are quite expensive, and relatively rare now, especially the second volume, but I almost always now check Pilbeam (rather than the NCL, which perhaps has gone a bit far for my taste), and then Reppenhagen. I get a better overall view of a plant, no matter if you call it M. magnimamma or M. seitziana, or M. rioverdense.....

Thank you, Chris. You have to love all the wonderful knowledge hanging around this forum.

All of these plants are of suspicious origin, so to speak, and can be hybridized making it impossible to put a proper name to. I had the impression that M. compressa tends to clump a lot easier than the others in the series, but that bristle tip will be invaluable.

I have John Pilbeam's book and find it very good; the Reppenhagen's books are unreachable these days. Perhaps you could convince the Mammillaria Society to issue a reprint...?

(as a side note, my plants were photographed before the first proper watering. They're not usually that battered...)

Still for sale on the net, you can look on "cactus-books.nl".
250€ for the 2 bands.

I'd love to, but 250€ is too much for me. I'll wait for a reprint or a bargain.

I would call numbers 1, 2 and probably also 5 M. magnimamma, whereas 3 and 4 are more M. compressa/centralifera-like.
Interestingly, the plant which is depicted in the Pilbeam book on p. 176 as M. magnimamma looks more like M. centralifera to me, whereas the plants shown on the next two pages are indeed M. magnimamma.
Conclusion: Make your own choice from all the suggestions!

By the way, I saw the two volumes of the Reppenhagen books being offered for only € 50 in the latest (April) issue of the German journal Kakteen und andere Sukkulenten.

Wolter ten Hoeve, The Netherlands.