C and D's Succulents
Basically the capsule. Dinteranthus capsules on average have more locules but otherwise have a similar structure. Lithops capsules mostly have five or six locules, sometimes seven in a few species, rarely four and very rarely up to 12. Dinteranthus capsules usually have 6-12 locules, sometimes up to 15. As you can see there is considerable overlap and the average capsule on the average plant wouldn't be convincing. More locules is generally considered an "advanced" feature, with five being the basic number that mesembs started from. Dinteranthus capsules are relatively large and the seeds small, so each Dinteranthus capsule tends to have a lot more seeds in it.What makes Dinteranthus vanzlii not a lithop?
There are other differences. Dinteranthus don't grow embedded in the ground, they are large and come in a limited range of colours (grey!) and patterns (dots and dashes) with hardly any windows. The bodies are more globular than cone-shaped and the top surface is usually keeled. D. vanzylii is the least extreme in most of these features. Lithops do have a number of anatomical features which are unique and allow them to adapt to arid summer rainfall habitats where essentially no other mesembs can live.
My personal thought is that the separation of Dinteranthus and Lithops won't last although it hasn't really been challenged in recent times. I believe that Dinteranthus will turn out to be every much as part of the Lithops clan as many Lithops species, possibly a very advanced part of the clan although in a different direction to the more advanced Lithops species. DNA testing has so far not clearly resolved the two although the close relationship is not in doubt.
--ian
Its tempting to think of any intermediate form as a hybrid but I've seen no evidence to back this up. D. vanzijlii does seem to be closer to Lithops than the other Dinteranthus, and not just in appearance. It hybridises readily with Lithops while the others are reluctant. It is the same as saying that L. julii ssp fulleri is intermediate in appearance between L. marmorata and L. julii ssp julii, therefore it is a hybrid between them. Maybe it is, maybe it isn't and the three just developed together into slightly different forms, or maybe they aren't even closely related and just arrived at the same point by different means.
I'm not sure I see the similarity with Lapidaria. They're both grey-skinned? Lapidaria capsules are subtly different to Lithops but closer than to Dinteranthus, although I don't see the differences are significant. Lapidaria have hints of some of the unique skin structures of Lithops, which Dinteranthus lack. Other features like nectaries are very similar in all three.
While these three, plus Schwantesia, almost certainly form a close group, it isn't clear what the internal relationships are. Its tempting to see the more shrubby forms as primitive and similar to some original ancestor but that may also be misleading. Ultimately the ancestors of all the mesembs surely had more leaves and longer stems, but Lapidaria could easily have developed from a stone plant back into a taller plant to fill some niche.
I'm not sure I see the similarity with Lapidaria. They're both grey-skinned? Lapidaria capsules are subtly different to Lithops but closer than to Dinteranthus, although I don't see the differences are significant. Lapidaria have hints of some of the unique skin structures of Lithops, which Dinteranthus lack. Other features like nectaries are very similar in all three.
While these three, plus Schwantesia, almost certainly form a close group, it isn't clear what the internal relationships are. Its tempting to see the more shrubby forms as primitive and similar to some original ancestor but that may also be misleading. Ultimately the ancestors of all the mesembs surely had more leaves and longer stems, but Lapidaria could easily have developed from a stone plant back into a taller plant to fill some niche.
--ian
Being a biologist, I like to speculate on the evolutionary processes that have produced what we see now. But as we know, its impossible to know exactly what happened during those 100s of millions of years, and speculation is one of our tools that can be used to delve into the natural history of each species.
Saying that, I do think that many species did come about from natural hybrid swarms, which led to intermediate forms,
But we better leave this talk alone, it may be considered unacceptable under cactiguide guidelines
Saying that, I do think that many species did come about from natural hybrid swarms, which led to intermediate forms,
But we better leave this talk alone, it may be considered unacceptable under cactiguide guidelines
Is it normal for C. ratum to flower at this time? I didn't realise this was an early species. Mine are too small to flower yet. Or maybe they've been doing it in secret when I wasn't looking
Have you not burnt off all those Gibbaeum flowers yet? I still have one late flower where the bud just refused to open.
There was an article in Bradleya last year about natural cactus hybrids and their role in speciation, also how this can be detected through various molecular techniques. It suggested that hybridisation was an important although not dominant factor in the creation of cactus species. This year Bradleya, not published yet, has an article proposing that genetic drift has been then dominant factor in cactus speciation.
Have you not burnt off all those Gibbaeum flowers yet? I still have one late flower where the bud just refused to open.
There was an article in Bradleya last year about natural cactus hybrids and their role in speciation, also how this can be detected through various molecular techniques. It suggested that hybridisation was an important although not dominant factor in the creation of cactus species. This year Bradleya, not published yet, has an article proposing that genetic drift has been then dominant factor in cactus speciation.
--ian
They could be twins. NOT! Amazing how much variation there is in this one species all coming from such a tiny area.
My adult L. viridis are fairly green, muddy green but still more green than anything else. The seedlings toast up brown and even red. Occasionally plants seem to turn up which are much more red than normal and it might be possible to isolate these as a cultivar one day. It probably won't be me though, its hard enough to get them to flower over here, let alone two specific plants at the same time for pollination.
My adult L. viridis are fairly green, muddy green but still more green than anything else. The seedlings toast up brown and even red. Occasionally plants seem to turn up which are much more red than normal and it might be possible to isolate these as a cultivar one day. It probably won't be me though, its hard enough to get them to flower over here, let alone two specific plants at the same time for pollination.
--ian
Lapidaria margaretae
Vanheerdea angusta
Stomatium sp. MG 1869.341
Namibia ponderosa left, N. cinerea right
needs more light than I can give it to grow w/o scars
Dinteranthus microspermus MG 1479.6
Jutterdinteria kovismontana, from seed, either MG 1532.8 or 1533, they got mixed up, and only one of them had these teeth and knobs
Jutterdinteria simpsonii, I think, or they may have been mixed up with the J. kovismonatana's
I got these seeds from Mesa garden labeled as Frithia humilis, but they are no Frithia, maybe a Ruschia or Rhombophyllum of sorts,
any one else get completely the wrong things from Mesa?, we could start a whole new thread on that topic!!
Vanheerdea angusta
Stomatium sp. MG 1869.341
Namibia ponderosa left, N. cinerea right
needs more light than I can give it to grow w/o scars
Dinteranthus microspermus MG 1479.6
Jutterdinteria kovismontana, from seed, either MG 1532.8 or 1533, they got mixed up, and only one of them had these teeth and knobs
Jutterdinteria simpsonii, I think, or they may have been mixed up with the J. kovismonatana's
I got these seeds from Mesa garden labeled as Frithia humilis, but they are no Frithia, maybe a Ruschia or Rhombophyllum of sorts,
any one else get completely the wrong things from Mesa?, we could start a whole new thread on that topic!!