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Thread: D. venusta "coccicaulis"?

  1. #9
    BobZ's Avatar
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    This is another of those taxonomy debates. The ICPS Database, according to Jan Schlauer, places them all as D. natalensis.

    Quote Originally Posted by [b
    Quote[/b] ]
    N: +[Drosera natalensis {Diels}]
    P: Pflanzenr.26:93 (1906)
    T: Clairmont near Durban, Natal, ZA, Wood 4901 (B)
    CLA: CAR-NEP-DRO-DRO-DRO-DRO
    L: ZA, MZ, MG
    XN: 40 {Debbert} ut [Drosera venusta {Debbert}], {Nicholas & K.Kondo}
    XNP: Mitt.Bot.Staatss.Muenchen 23:434 (1987), Chromosome Sci.2:49 (1998)

    N: [Drosera venusta {Debbert}]
    P: Mitt.Bot.Staatss.Muenchen 23:432 (1987)
    T: Oteniqua Mts. N George, Cape, ZA, P.Debbert s.n. (M)
    S: =[Drosera natalensis {Diels}]

    N: ~[Drosera coccicaulis {Hort.Westphal}]nom.nud.
    P: Carniv.Bestandsl.:1 (1991)
    S: =[Drosera natalensis {Diels}]

  2. #10

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    Wisely so in my opinion. Taxonomy often goes deeper than the visual impact of the particular individual....a good thing in S. Af. droserae because there are so many different and unique forms. Who knows how those forms arose...a situation similar to the taxonomy of Sarracenia species hybrids....very complex because many backcrosses can and do happen where populations are sympatric. I feel a taxonomy for South Africa needs to be based on something other than Species Novae publication, and collection data is so essential to understanding the diversity in S. Af. it should be appended to the binomial ideally at variteal status (this is not the current fashion in Drosera taxonomy). There is very little to be gained in understanding (especially for the horticulturalist) without such data, and probably not much even with it! Here in the USA Drosera capillaris presents vastly different forms over its range, but all such are just simply that species. WHy are they so different looking? Go ask the eight ball.

    Remember too, that Diels published at the turn of the 18th century, and that monograph is still the word of God. Schlauer's revision published in the CPN was interesting, but a more detailed monograph is needed, hopefully by the turn of the next century, lol. Relying on literature and micromorphological analysis of selected individuals to accept or reject a Species Novae is perhaps not ideal, but it's the best we have. The concept of "type" is utterly useless without having seen a range of diversity both in the field and in the herbariums where such "types" have been placed, hopefully by those who looked at many, many individuals, and then arrived at a synthetic concept of what characteristics made a "good" representative of that species.

    This means more than touring S. Af. for a month, picking up a bunch of different lookig droserae and then publishing those forms as new species. Without the extensive and expensive field work, such matters are quickly referred back to Diels, even those with some validity (real or imagined) and Authority gives the boot to weak publications.

    One thing is for sure, no one is going to tackle the S. Af. populations with pith helmet on and notebook in hand. Paul Debbert tried (and still has boot marks on his butt for it). As a study subject in academia, it would be sure death for the PhD candidate. (Similarily, no one wants to study the Drosera capillaris issue here, although the subject is crying for it.)

    Hats off to Allen Lowrie for his work with the Petiolaris Complex, and to his countryman Robert Gibson for his immense study of the Drosera peltata complex!!! Field and herbarium study are essential to recognizing members of a particular population. Both have been at it for decades.

    I've grown many D. natalensis forms, many D. venusta, and many D. coccicaulis from seed both native and sent by other growers from all over the world. Trust me, the only way to differentiate is with an eight ball.


    You ask the eight ball a question, like, "Are Drosera natalensis and Drosera venusta the same species?" and the eight ball replies, "Ask again later".
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    Holy crap! Awesome reply!

  4. #12
    Metal King
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    Please allow me to retract my "cleared it up" comment, too- tho your explanation DID make it more clear why I have such problems getting even a guess as to what the heck it is I'm growing
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  5. #13

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    Hello,

    This discussion only shows, why it is so important to have location data for the plants. Location data, as exact as possible, are much more important for me than giving a name for the plant.

    I too have problems with the species-concept as used with plants. There is no good definition of what a species is. In the case of Sarracenia, you can easily find arguments, that they all belong to just one species.

    Personally, i have problems with some listings of the ICPS-Database. D. venusta/natalensis is one of these. I think, that D. venusta deserves at least subspecies status. For me D. venusta is distiguished from D. natalensis by the leafshape and the form of the seeds. I know, there is much variation and plants, that do not fit into any of these species. Don't forget, that D. dielsiana plays a role in these plants as well. I do not like the idea to call any plant of the complex just D. natalensis. In fact, some of the D. venusta forms i am cultivating are really very differnt to some of the D. natalensis. There is no trained eye needed to see the differences.

    Please do not call any plant D. "coccicaulis", that you didn't get as such. There is no real difference to many other D. venusta forms. The plants are just collected somewhere else. In this special case i think it is best to stick to the name D. "coccicaulis" (if you got it as such!).

    Finally, some pictures of my plants. I hope i can illustrate, what i tried to say above.

    seeds of D. natalensis "Debbert"

    larger picture

    seeds of D. venusta (collected between George and Outdshorn)

    larger picture

    I think, the difference can easily be seen. It is stable in all my cultivated plants.

    some pictures of D. venusta/natalensis:


    larger picture
    D. venusta - George,Outdshorn


    larger picture
    Drosera venusta - Tsitsikama National Park


    larger picture


    larger picture
    Drosera natalensis - Natal

    D. natalensis has rounder petioles, that are leading into a more/less round lamina, while the petioles of D. venusta are much wider and are more/less searnlessly ending in the lamina.

    Christian

    P.S.: If anyone has spare seeds of D. venusta/dielsiana/natalensis (or similar) with location data, please let me know! I am really interested in plants from this complex!

  6. #14
    白人看不懂 Drosera36's Avatar
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    While we're on the topic, I have a question about my D. venusta plant. The leaves it grows are completely upright, and when new leaves form, they get kind of crammed in the center of the plant, and then eventually, a leaf will move downwards and then stay more horizontal. After a few weeks, the leaf loses dew, and then stays as it is, maybe bending a bit more downward. The plant is a reddish color, lots of dew. I think maybe the spectrum of light that it is given isn't right, and that's why it is doing this. The leaves it makes are of normal size, they aren't getting any smaller. It looks a lot like the D. venusta - George,Outdshorn picture. What could be the problem with it?







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