name please

[scousetigger]

I think this is a Mammillaria of some sort, but not sure. I would like to know also why the new growth has grown elongated whereas all the rest of rhe plant looks more like a brain?
Sue

[Guest]

Sue,

It is a cristate form of the elongated bit, a cliestocactus I think but not my area so somebody may correct me. You can cut off the normal growth and let it dry for a couple of weeks and it will root quite easily.

[NickT]

I don't think it's a mamm either Bob. I think the one your thinking of is this one sue but you can see the difference in spines

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[Phil_SK]

Surely it's a cristate Cleistocactus winteri, formerly known as Borzicactus aurespinus, Hildewinteria aurespina, plus several other names.

[Bill]

I've got one of these too, had it for about 4 years or so and all of a sudden this year mines put up "two long bits". I think Bob's probably in the right area name wise, never bothered with naming mine.

[Phil Hocking]

I was given one just like yours Sue, only mine hasn't produced a straight piece yet. As the others say, definitely not a Mammillaria and most likely a Cleistocactus.

The difference between the two parts of the plant is in the growing point. Normally it grows from a single point radiating outwards but sometimes the point elongates to become a line; if it becomes a very long line all it can do is fold on itself. Hence you get a cristate form.

The other sort of 'deviant' plant is the monstrose form, in which multiple growing points arise. I think it was you who posted a picture of one today - Cereus peruvianus monstrose as I know it, but identified as a different species on the forum (can't quite remember the name).

Phil in Somerset, UK

[scousetigger]

Would that be the Cereus hildmannianus var. monstrose?

[iann]

Same thing. C. hildmannianus is the current valid name although not the easiest to spell

[Phil Hocking]

That's the one. I don't know if it is a synonym or, if not, what the difference is. I can't find much on Google about it. Maybe someone can enlighten us. There seem to be montrose forms of several Cereus species, sometimes called monstrosus. I have one that I bought for the office to counter the emissions from computer screens (well NASA said it worked!). We had several straight Cereus peruvianus plants too but they were banned from the office on health and safety grounds after a cleaner pricked her finger on one.

Phil in Somerset, UK