> I've grown both D.coccicaulis and D.natalensis, the latter from 3
>different locations in the Natal Province, and I do not believe these are
>the same species. If D.coccicaulis is a robust form of any species, I
>would say D.dielsiana.
I have studied living cultivated specimens of rather numerous different
clones of all species (and synonyms) you mentioned to some extent.
Variability is considerable but you can at least sort out _D.affinis_ (an
ascending species more closely related to _D.madagascariensis_; it seems
your plants are horribly misidentified if they even remotely approach any
of the rosetted species!) and _D.cuneifolia_ (=D.admirabilis) which has
very distinctive styles (with knob-like stigma and only basally bipartite,
somewhat similar to those of _D.slackii_) and large, broad petals.
_D.dielsiana_ can (mostly) be recognized by the bipartite (not repeatedly
split) styles and shorter (more ellipsoid) seeds. But here difficulties
begin. There are transitory specimens which grade into _D.natalensis_
(having moderately divided styles and seeds which could be called shortly
fusiform). One point of this series of variants is represented by
"D.venusta" or "D.coccicaulis" nom.nud., the latter being an especially
robust plant (and therefore also displaying a feature of _D.aliciae_!). On
the basis of micromorphological analysis, both are IMHO better placed in
_D.natalensis_, however.
The greatest problem is distinction between _D.aliciae_ (of which different
ploidy levels seem to exist) and _D.natalensis_. There are specimens which
simply cannot be assigned to any of the two species with certainty. Perhaps
it would even be better to include these two in one single species,
therefore. For the time being, a tentative distinction can be based on leaf
texture and number combined with flower colour (like OBERMEYER-MAUVE has
done it in her treatment of the genus in Fl.S AF, 1970). But the number of
indeterminable specimens (all of which instantly labelled by fanciful fake
names in the horticultural trade which inevitably make their way to
scientific literature) is increasing.
>After having had a quick look at S.African
>Drosera herbaria at Kew and Paris, I think there might be much more than
>we imagine in this D.coccicaulis/ dielsiana/ natalensis/ aliciae/
>venusta/ admirabilis/ cuneifolia/ affinis/ nidiformis/ etc. group.
Yes, more variation, certainly not more species (I regard 4 of the 9 names
you mentioned as synonyms). I have sketched above that we are talking about
3 or even 4 different groups (not one group) here, already.
>Well,
>at least we have seen that there is still much confusion and that some
>GOOD sorting out is needed. Knowing from experience how hard it is to
>study these small rosetted Drosera through herborized specimens,
They are not small, nor is it impossible to study the features I would
regard as taxonomically significant (style, seed, stipule morphology) in
dried specimens.
>I would say that extensive field work would be needed.
Agreed (plus the application of an appropriate species concept!).
Kind regards
Jan