[MikeHardman]

This small hummock-former has been flowering modestly for months now, after being more floriferous in the spring.
The leaves on my plant are shorter than those on many similar plants, and rough-textured (by dint of surface form, not hairs), and mucronate. So I don't think it is Delosperma cooperi or sutherlandii.

I think it may be Drosanthemum. Perhaps D. floribundum, looking at the leaves in this photo (http://www.leserre.it/dbimg/drosanthemum-floribundum_1973_drosanthemum_floribundum.jpg)
But other images of D. f. have different-looking leaves.
Of course online images come with no guarantees of being correctly named, though those on the MGS web site and forum stand a better chance than many!

[oron peri]

Mike it is very difficult to say from this photo as scale is not clear as well as the color and form of the leaves.
If you get a better photo it would be better, leaves and growth habit are the important part as some of the Drosanthemum and Delosperma have identical flowers.

[MikeHardman]

Hi Oron,

Thanks for looking.
Here are some more photos.

Dimensions:
- roundish mound about 30cm across at the moment
- flower diameter 20-24mm
- leaf length up to 29mm
- leaf cross-sectional diameter up to 5mm
And the leaf cross-section is almost round; just slightly flattened on the upper 'side', definitely not faceted.
You will see the distinct, reptilian-like, texture to the surface of the leaves, and the little cluster of bristles at the end.
The photo of the whole plant shows the flowers being unopened while it is in the shade. When the sun gets onto them, they will open.

[oron peri]

Mike,
Sorry i forgot this one,
This plant is in commerce under the name Drosanthemum hispidum, but i'm not sure it is the correct name.
There are 95 species of Dros. a few look very similar.
Hope it helps...

[Alisdair]

Drs Richard Dean and Sue Milton-Dean who run a South African nursery as part of their veld restoration work in the Karoo have a worksheet on Drosanthemum hispidum in which the pictures do look slightly different from Mike's plant, notably in absence of terminal bristles, in leaf shape (but that could be cultivation), and in the appearance of the raised water cells. You can see their worksheet by clicking here.

[Alisdair]

Sue Milton-Dean has now kindly written to tell me that Mike's plant is a species of Trichodiadema - she says that the bristles on the leaf tips are the give-away.

[oron peri]

Alisdair i think we are not there yet.... as Drichodiadema is not a vallid name at the moment...

[oron peri]

I think it might be Mesembryanthemum barbatum [Syn. Trichodiadema barbata], only that both names are not vallid at the moment

[MikeHardman]

Damn its good to get some smart heads together!
Thanks guys.
I know we don't have an accepted name yet, but it in any case it strikes me as a cracking example of the virtue of the MGS Forum!

From the photos I have found on the internet, my plant matches extremely closely with Trichodiadema intonsum
(intonsum = unshaven). So that might turn out to be the species epithet, even if it ends up in some other genus.

The Plant List confirms the questionable status of the genus - http://www.theplantlist.org/tpl/search?q=Trichodiadema.
And for Trichodiadema intonsum Schwantes in particular, it states: "This name is unresolved, but some data suggest that it is synonymous with Mesembryanthemum intonsum Haw." (http://www.theplantlist.org/tpl/record/kew-2436681)
Mesembryanthemum intonsum is also an unresolved name. Hey ho!

[Alisdair]

Yes, Mike and Oron, according to The Plant List Trichodiadema is indeed unresolved as a genus name, but when you  see "Unresolved" in The Plant List you shouldn't necessarily assume that the name is incorrect. As the compilers of the List always make clear, it is very much a work in progress.
Always check the confidence level for the status given in the List. In this case the confidence level for that "Unresolved" tag is stated to be low, and the people currently working on South African flora generally do now use Trichodiadema - see e.g. van Wyk and Smith's recent Regions of Floristic Endemism in Southern Africa: A Review with Emphasis on Succulents.
On this forum when a name is treated by The Plant List as "Unresolved", we generally don't alter it if the confidence level is low, and if it's in general current use among people expert in the genus concerned.
Given that Dr Milton-Dean is working in this exact field, I think it's quite reasonable to use her Trichodiadema for this interesting plant - and rather exciting to have a plant that there is clearly so little taxonomic agreement on! (Wait till we get on to the trickier byways of cyclamen nomenclature.... )

[MikeHardman]

Alisdair - Right-o'; I'm happy to go with Trichodiadema for now (we all have to leave a little room in our expectations for plant names to change, anyway!)

Oron - barbata - could be. Looking at Google images for both barbarta and intonsum, there is variation in the bristliness of both species' photos (not necessarily of the species themselves). I homed-in on intonsum because I happened to find a good photo showing bristles like mine (well, it's 8pm now, so you'd expect me to be a bit bristly of cheek!)

[MikeHardman]

This is an instance of where a common name could be less controversial than a botanical one, and thereby more consistent in common parlance.

But I don't seem to be able to find a common name for it  
I think 'crown of thorns' (taken from the genus, referring to the bristles at the leaf tips) seems entirely appropriate and useful. It would apply to the genus as a whole, of course. And I don't think we need to worry about confusion with starfish of the same name.

Alisdair,
Do Drs Richard Dean and Sue Milton-Dean have a common name for it?
I notice T. intonsum/barbata are not in their list (http://www.renu-karoo.co.za/nurserystock.htm), though it does include T. mirabile, for which they give the common name 'hairy nipple', or 'hairy nipple vygie'
(Vygie (plural vygies) is a common name for any of the species of Mesembryanthemacae, so Wikipedia tells me.)

[John J]

Sorry, Mike, but 'Crown of Thorns' has already been claimed by Euphorbia milii. All these name changes are too much for an ageing brain to handle!!

[Alisdair]

No, even from your clear pictures they weren't able to define the species.
For all the usual reasons, best to stick to a latin name, and as Trichodiadema seems to be the one the South Africans are working with that would be the preference at least in the interim before the Trichodiadema/Mesembryanthum question is resolved - no doubt years away. As John says, crown of thorns would be unwise anyway, as other plants from other families already have the name in the more Biblical sense, most familiarly Euphorbia milii var. splendens, which incidentally does very well for us completely unwatered, in our hot Greek garden (see picture below, taken one January).
I suspect the locals would call it a vygie, but alas that's just what they call any of the mesembs (Aizoaceae).

[Alisdair]

Carole emailed me this link to a highly relevant article in today's UK Daily Telegraph. Thanks, Carole!