Not a mammilaria ?,

[Tina]

I purchased some plants from a friend earlier this year and in the batch of plants are these three, supposedly mammilaria peresdelarosae ssp.andersoniana.
One seems like an imposter, not being a cactus expert any suggestions, my thought was escobaria or echinocereus

[Stuart]

The one in the middle is like the sort of plant that turns up in the identification part of the Judges Course. It doesn't look like anything I've seen before, it's not impossible that it could be a monstrose form of Andersonii/Andersoniana. I'd always called the other two var Andersonii but it seems it may be Andersoniana? With straight ribs it doesn't look like a Mammillaria, whoever grew it may be able to throw some light on the source of the seed. I think you'll have to wait for a flower.

Stuart

[habanerocat]

It looks like an Echinocereus hybrid with some davisii inside in it.
There's a 'brevispinus' form, but not so woolly.

http://www.cactus-art.biz/schede/ECHINO ... spinus.htm

If it is davisii like, it should be putting out buds fairly soon.

[Tony R]

... I'd always called the other two var Andersonii but it seems it may be Andersoniana?
Stuart

Originally named as:
Mammillaria perezdelarosae subsp. andersoniana W.A.Fitz Maur. & B.Fitz Maur., Cact. Succ. J. (Los Angeles) 73(5): 264 (2001).

Since Mammillaria bombycina subsp. perezdelarosae is also an accepted name then we might call it fa. andersoniana although I don't think this has been formally published anywhere?

Time will tell with the 'Ugly Duckling' in the middle!

[Aiko]

If I would have to guess, the middle one looks like a M. perezdelarosae subsp. andersoniana mixed with some Echinocereus.
But I also would not rule out the possibility that it is just a M. perezdelarosae subsp. andersoniana gone rogue.

An odd one, but I do like it!

[Stuart]

Thanks Tony, it'll be Andersoniana in the future then. I met the Fitzmaurices when checking in at a Tucson motel years ago. They spoke to me because I had a copy of Cactus World or maybe BCSS Journal in my hand at the time. I've no idea why I had it in my hand at the time and to add to the coincidence, the Fitzmaurices had an article in it.

Stuart

[RayW]

Tina; I think it is just a sport of Mammillaria perezdelarosea, as Aiko says there is always 1 in a packet of seed that goes rogue.
One thing is for certain it is not an Echinocereus.

Stuart; Wow that is a coincidence.

[habanerocat]

I'm not seeing spirals here, I'm seeing ridges. Perhaps Tina can confirm.....

[iann]

These should be flowering about now. That would answer a lot of questions.

[Chris43]

I can't see any evidence that there is a separate axil at the base of the tubercle on the plant in the middle, though the clarity of the photo coud be better. Maybe my eyes are not good enough, always possible!