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Thread: Drosera seed pics

  1. #1

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    Well as we all know all of the upright (not including the climbing D. macrantha) Drosera in South East Australia have been reduced to the same species, D. peltata. Howerver these "forms" grow side by side, look different, are geneticly isolated from each other, have different looking flower structures and here are the seed!



    From left to right with 4 seeds of each, D. auriculata, D. sp. "foliosa", D. peltata.

    Oops here I go again I mean D. peltata, D. peltata and D. peltata...

    Sorry about the sarcasm couldn't help myself [img]http://www.**********.com/iB_html312/non-cgi/emoticons/biggrin.gif[/img] [img]http://www.**********.com/iB_html312/non-cgi/emoticons/biggrin.gif[/img]

    I took the pics by holding my camera against the eye peice of my disecting microscope. It worked supprisingly well. Once again Tamlin was right, it was well worth inspecting the seeds...

    George

  2. #2

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    Here is a nice pic of a D. sp. "foliosa" I took a few weeks ago at a VCPS field trip.



    I do like these plants. They are always an intense green, even in full sun.

    George

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    Excellent work George!!! I hope you will be able to take many more seed photos. I will be putting together a good selection for you to work with, I simply MUST get a dissecting microscope if you can get results like these!!!

    BAsed on the scale in these photos the Drosera lamina look to be huge. What a beauty! Thanks again for sharing the *fruits* of your labor.
    "Grow More, Share More"

  4. #4

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    George,

    To answer your question on what makes a species in this case:

    1) Seeds more or less narrow-ellipsoid, occasionally oblong-cylindrical, 0.3-0.5 mm long; basal unbranched part of style 0.1-0.3
    mm long; sepals 2-4mm long, hairy or glabarous; petals 5-6 mm long: a subsp. D. peltata

    2) Seeds narrow-linear to oblong-cylindrical (0.5-) 1 mm long. Glabarous; petals 7-8 mm long: a subsp. D. auriculata

    If the presence or absence of indumentum on the sepals is used as a criterion for separating D. auriculata from D. peltata, then it is unjustified to maintain these two as separate species while regarding other species formerly recognized by minor characters. e.g. D. lunata, as synonyms of D. peltata. If we regard the shape of the seed as a fundamental feature to distinguish these two species, then some specimens which are classified as belonging to D. peltata (because they have hairy sepals), would have to be regarded as D. auriculata, even though their other features do not support such a separation. The presence or absence of indumentum on the sepals is of secondary importance and the variation in shape of the seeds is such that there is too much overlap of character to support maintenence at species level.

    The best solution, based on an assessment of the wide range of variation within the population (e.g. as found in Australia and New Guinea) and accounting for the existence of distinctive sympatric populations (e.g. as found in Australia in parts of the geographical range, is to recognize two infraspecific taxa based on a combination of characters. The morphological differences observed between these two taxa represents infraspecific variation. Accordingly D. auriculata is reduced to a subspecies of D. peltata.

    Other distinguishing criteria are in D. auriculata the lamina of the basal leaves are flabellate and folded, infloresence 1-2 flowered, erect stem flexuous.

    Hope this helps!
    "Grow More, Share More"

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    "Grow More, Share More"

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    "Grow More, Share More"

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    Ok, acording to my 10th grade biology "the defination of a species is any group of plants\animals\micro organisms that when hybridized produce fertile offspring"[img]http://www.**********.com/iB_html312/non-cgi/emoticons/tounge.gif[/img]
    [img]http://home.**********.com/users/pondboy/Neps/Neps%20sig..JPG[/img]

  8. #8

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    Pond Boy, as my 1st year chemistry lecturer said "Forget everything you were taught at high-school, it's all wrong"... although that is a good place to start segrigating species [img]http://www.**********.com/iB_html312/non-cgi/emoticons/biggrin.gif[/img]

    Quote Originally Posted by [b
    Quote[/b] ]"If we regard the shape of the seed as a fundamental feature to distinguish these two species, then some specimens which are classified as belonging to D. peltata (because they have hairy sepals), would have to be regarded as D. auriculata, even though their other features do not support such a separation."
    This is very interesting as all the plants I have seen are consistent in seed shape and sepal apearence. Long seeds = smooth sepals, oval seeds = hairy sepals. So from what I have observed these two criteria are supportive of each other. I have only been able to sample a (relativly) small range within a few hundred km of Melbourne. Although this matches up with work being done in other parts of Australia. There are a few odities out there which do have some intermediate characteristics (D. gracilis), but these hold true throughout thier range and as such these populations are beleived by some to be distinct species that simply to have some characteristics of two other species.

    Quote Originally Posted by [b
    Quote[/b] ]"Hope this helps!"
    [img]http://www.**********.com/iB_html312/non-cgi/emoticons/rock.gif[/img] Thanks a heap, where did you get this information from?

    My brain hurts...

    George

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