Help welp identifying a large Mammillaria please!

[Mike]

This is a plant I was given to 'rescue' a while back and it has finally rewarded me with a few flowers, can anybody help it gain a name as well? It's a six inch pot.
Mike

[Mike]

And slightly closer...
Mike



Post Edited (08-01-06 13:54)

[iann]

Looks a lot like one of the rhodantha clan.

[Anthony1]

Hi Mike

It looks like M.haageana ssp.acultzingensis.


Regards

Anthony Morris

[Mike]

Thanks both for your suggestions.

I'm now a little confused - it's very like M. haageana acultzingensis (especially the picture in John Pilbeam's book) but he says it grows to 8-10cm (my plant is 22cm). Mind you it was only described in 1994 so maybe he'd only seen 5-year plants at that time!

...and it's very like M. rhodantha aureiceps as well.

In fact the descriptions for the two plants are nearly identical. They couldn't possibly be...the same could they?
Mike

[iann]

I may not be reading the same description as you. M. haageana usually has two spines but sometimes up to four. This plant appears to have 6. M. haageana at 22cm would be a monster, larger than I've ever seen although not unthinkable. M. haageana tubercles are quite distinctive, rounded near the tip, but square at the base so that they fit together very neatly on the body of the plant. Usually bare axils, at least on a good part of the plant.

M. rhodantha aureiceps is described as having 6-7 central spines. Other subspecies have varying numbers of central spines around 6 or so, although often they are a darker reddish colour. Subspecies rhodantha can have yellowish spines. Also subspecies pringlei, but they are usually long and curved. M. haageana central spines are generally up to about 1cm, while M. rhodantha are up to about 2cm, exceppt for subspecies pringlei which are even longer. Tubercles on all M. rhodantha are rounded right to the base, larger than M. haageana and typically cylindrical near the base tapering to a conical end. Fine hairs in the axils are common, wool on the new growth, but not much wool on older parts of the plant. M. haageana tends to have more wool in the axils, less on the new tubercles.

It would be helpful to have accurate spine counts and a description of the tubercle shapes from the horses mouht, plus whether there are bristles in the axils. The plant appears to have an abrupt transition from wooly tubercles on the new growth to quite wooly axils on older growth, with some strange deformities with clustered spines near the transition area. Probably just a change in culture a couple of years ago but maybe something else?

[Mike]

Many thanks for the info, Ian

Anderson and Pilbeam both give haageana up to four central spines, and you're right my plant has six (about 1-1.2cm long). It also has - as you suggest - woolly tubercles on the recent new growth and woolly axils beneath (the latter again suggesting rhodantha). Tubercles are what I would describe as a slightly squashed conical shape, without any obvious squaring at the base. M. rhodantha it is (And likely M. rhodantha aureiceps at that).

And you're also right, there's are some strange growths near the top - in fact two rings of what look like new growing points. I suspect now I've finally got it to start growing again I should be careful not to water too much and end up with a top heavy plant!

Mike

[iann]

M. rhodantha it is (And likely M. rhodantha aureiceps at that)

Maybe! M. rhodantha doesn't usually have much wool in the axils, especially below the flowering zone.

A similar-looking wooly plant would be M. columbiana. Its big too! Another is M. flavicentra, not quite so big but probably big enough.

[Mike]

That'll teach me to think I've taken a step forward in my understanding of Mammillaria taxonomy!

The top 95% of the axils of my plant are certainly woolly but they all show signs of having flowered in the past.

M. columbiana certainly looks similar, Especially M. c. columbiana. I notice that Pilbeam says this has '4 or 5' central spines 'but 3 and 7 are also seen' and shows a picture with clearly six! , However, according to my books it doesn't get more than 6cm in diameter, whereas mine is about 11cm across (exc spines).

M. flavicentra, as you suggest is also similar, but according to the books has shorter and more numerous radial spines than M. rhodantha (and my plant) and central spines likewise shorter than M. rhodantha.

So, I think I shall stick with M. rhodantha, but with a greater respect for the difficuty in disentangling these 'species'. Thanks for guiding my education!

Mike