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06-06-2008, 11:02 AM
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Marriot was a famous orchidist during the discovery years ih the mid 1800's.
I agree that it should be simplified for the hobbyist etc., but there is a strong basis for the new genotype classification. What pains me is that some are listed in more than one genus, such as prosthechea and anachilum and panarica and epidendrum.
It will get more complicated for awhile now that there is DNA identification of genera specifics, then it will simplify simply due to the fact the over-complications will result in people revolting against ... that's what we're doing NOW, isn't it?
The needs of scientific research and regular hobbyists and growers are very different. There is no reason for an "either/or" system. There can be and should be two systems. No one system could possibly satisfy both needs.
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08-06-2008, 01:28 AM
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The only test of taxonomy is time. Putting everything in South America into Cattleya was a contentious compromise between horticulture and molecular taxonomy (leave traditional taxonomists out of this mess). An equally viable alternate approach has been proposed by groups in Brazil and France - essentially Sophronitis is just the S. cernua complex; the Sophronitis coccinea group and the Laelia pumila group become Hadrolaelia; the rupicolous Laelia flava group returns to Hoffmannseggella; and the Laelia purpurata group becomes Brasilaelia. Both classifications have merits and their proponents.
Just wait to see what is happening to Oncidium and will be happening to Vanda!
Eric
p.s. To Steve, the plural of genus is genera.
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08-06-2008, 05:43 AM
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Quote:
Originally Posted by orchideric
p.s. To Steve, the plural of genus is genera.
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How very embarrassing! I should have written that but caught up in the moment! My bad.
I really dont think that hobbyists should have any say what-so-ever in the naming or renaming of orchid genera (genuses!). My point is that it seems like the new classification system seems to suit many (not all) of the scientists making the changes because their names are added to either the new genus or the new hybrid name for Blc, Slc, etc. It also does not help that our trusty AOS automatically accepts EVERY single change that comes along. They lose their credibility by never challenging anything! At some point, you would think AOS would say something that in some way shape or form shows that they are paying attention! After a while, if all the visitors to a secure location get in hassel free, its pretty safe to assume that the guard is asleep! That's my point! I have little doubt that DNA testing is highly precise in showing the differences between species and their alleged allies, but I have the distinct feeling that it is the human interpretation that currently has no "guidline" as to how much difference actually constitutes a separate genera. If I were wrong in my assumption (and yes, I am very aware of the ASS-U-ME breakdown) I doubt that there would be a fairly regular re-constitution of the genera under, for example, Laeliinae. Am I wrong?
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08-06-2008, 11:34 AM
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Just my . I respect everybody else’s opinions. But, allow me to explain mine. I can’t agree with, when they say lumping ALL Sophronitis (as it is undertood today by Kew, including former Brazilian Laelias) with Cattleya is a scientific based decision. It is not. It suits no matter what purpose, but science. Let me try to explain why and for that we have to get a little back in time. You see, the decision of lumping Brazilian Laelias with Sophronitis was not mandatory, I mean, the DNA analysis of the Laelia and Sophronitis groups did not force the conclusion that all Brazilian Laelias were Sophronitis. The DNA analysis only gave an indication that Laelias and Sophronitis were related. Just this, and nothing more than this. And, most important, the degree of relationship between these two groups did not force the conclusion that they were the same and in consequence should be put together. That was a human decision. Reading the original paper published by C. Van den Berg and his later explanations, he clearly says that there were at least two possibilities: first, lumping to Sophronitis and second, split Brazilian Laelias into smaller genera, and both were perfectly acceptable under de DNA analysis (the last part of this phrase is my conclusion, otherwise they wouldn't have wasted time long discussing the possibilities, as he says in his explanations). Cassio and his group decided for the first possibility following the recommendation that the nomenclatural changes should always have in mind to simplify, not to complicate the understanding of the relationship between groups of plants. In their opinion, lumping would simplify. But, there were unsolved problems. The same DNA analysis showed that the Cattleya maxima is related to Cattleya, but also to Laelia... the degree of relationship perfectly authorized to split it to Laelia, but nothing was done. The same DNA analysis also showed that Cattleya bowringiana and its group of species (now Guarianthe) were related between them, but also kept a degree of relationship with Cattleya... and despite that, they were split to Guarianthe! You see? The same DNA analysis serving to do nothing (Cattleya maxima), serving to split (Guarianthe) and serving to lump (Laelia into Sopronitis). Can these decisions keep coherence when you know that the differences are only of degree of relationship?
Now they are speaking of lumping all Sophronitis (Kew sensu) with Cattleya... Doesn't it sound a little bit strange that this is OK for the Brazilian former Laelia and Sophronitis and is not OK for the Guarianthe species, let alone for the Rhyncholaelias, that also are undoubtedly related to Cattleya? Why not lumping these two groups too?
Everything here is a matter of the degree these groups are related and there’s no doubt they are related. So, the same reason that gives 'support' for the decision of lumping Sophro (Kew sensu) with Cattleya also obliges to put in the same basket Guarianthe and Rhyncholaelia. Why this is not being proposed? No, in my opinion, this is not a scientific decision. I can't see anything scientific in this lumping fever that is valid only for the Brazilian orchidaceae.
The article in the AOS Orchids magazine gives a perfectly clear indication of the truth behind the scenes... the entire article is dedicated to speak about how simple and easy the new hybrid orchid names are going to be! Not a word on the scientific reasons of the proposed change!
Last edited by Rosim_in_BR; 08-06-2008 at 01:34 PM..
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08-06-2008, 12:52 PM
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Thanks for this interesting and informative thread. I have to agree with Mauro and maitaman (well, also disagree with maitaman). While I am a hobbyist, in a sense, I am really a biologist with an orchid habit. I believe that distinctions between groups should be rooted in science. As a hobbyist, it's nice when things are easy. But as a scientist, I strive to get things correct, no matter how easy. The complexity of this family is part of why I love it. But irrespective of my degree of involvement or commitment to my 'hobby', a plant is what it is (A rose by any other name would still smell as sweet).
OK, I'm confusing myself! What I'm saying is, an orchid IS what it IS. It always has been. It always will be. Calling a giraffe a dog because it's easier to spell and pronounce doesn't make it any more of a dog. It just makes the dog breeders confused! If we know that something is different - split it. If we KNOW it is the same - lump it. But arbitrary name changes just to make them fit on a plant tag at an orchid show is just plain sophistry.
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08-06-2008, 04:04 PM
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Quote:
Originally Posted by Rosim_in_BR
Can these decisions keep coherence when you know that the differences are only of degree of relationship?
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Exactly! It seems like there is no standard for how close or distant a degree of relationship needs to be in order to determine whether or not a species or genus should be lumped or divided. Why doesnt Kew or AOS or someone else come up with a definitive way to determine kinship? For example, maybe a 1% difference in DNA could constitute a significant enough difference to separate two species into two genera. Clearly, I just pulled this number out of the air, but you get my point. Is there a system like this? I have a feeling the answer is 'no' because of the arbitrary nature of the 'scientific' reorganization of Laeliinae.
Quote:
Originally Posted by Rosim_in_BR
The article in the AOS Orchids magazine gives a perfectly clear indication of the truth behind the scenes... the entire article is dedicated to speak about how simple and easy the new hybrid orchid names are going to be! Not a word on the scientific reasons of the proposed change!
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I definitely agree with Mauro that simplifying for the sake of simplifying is wrong, as is simplifying for the sake of hobbyists. When reclassifying genera, science should be the ony reason for doing so. Dont get me wrong, I would love to see all these genera lumped into one genus, but that my own selfish desire for a more simplistic view!
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08-06-2008, 06:03 PM
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But the point everybody is avoiding is whether you want divergence defined solely by change in the DNA. Science is not just DNA despite what a raft of pundits would have one believe. Two groups of orchids may be closely related based on shared DNA but wildly different if their biology has diverged - say one group being bee pollinated while another is moth or wasp pollinated. Sometimes the DNA supports these distinctions as in Lycaste (bee pollinated) versus Ida (moth pollinated). In other cases the divergence is less advanced and it becomes a judgement call of where to draw the lines when the DNA says one thing [to a degree!] and the gross floral morphology related to pollination says something else. These nuances are outside the scope of those doing molecular systematics.
Eric
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08-06-2008, 07:18 PM
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Quote:
Originally Posted by orchideric
But the point everybody is avoiding is whether you want divergence defined solely by change in the DNA. Science is not just DNA despite what a raft of pundits would have one believe. Two groups of orchids may be closely related based on shared DNA but wildly different if their biology has diverged - say one group being bee pollinated while another is moth or wasp pollinated. Sometimes the DNA supports these distinctions as in Lycaste (bee pollinated) versus Ida (moth pollinated). In other cases the divergence is less advanced and it becomes a judgement call of where to draw the lines when the DNA says one thing [to a degree!] and the gross floral morphology related to pollination says something else. These nuances are outside the scope of those doing molecular systematics.
Eric
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Delination of genera based solely upon DNA systematics makes sense from a quantitative point of view. You can have an exact number on how many differences exist between species and allies, where-as traditional morphological classification depends more upon quantitative data, such as method of pollination. Which is better? I honestly have no idea, though I think the current problem of constant reclassification of members within Laeliinae can be directly attributed to the use of qualitative, and therefore subjective, classification methods. Logically, it would seem that differentiation of genera based on quantitative data would solve this problem because we can then set a standard for speciation based on some genetic distance between said species. Is pollination by moth vs. bee really enough to separate a genus into genera? Again, I dont know but it would seem that a DNA based classification system might give more insight into genetic differences that exist in both the morphological and spacial realms. Basically, DNA analysis can give a better picture of when differentiation occured as opposed to how, thus showing a clearer picture of the family tree than can traditional morphological techniques which are based on human interpretation.
Last edited by isurus79; 08-06-2008 at 07:22 PM..
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08-06-2008, 07:45 PM
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Steve you are wrong about changes in the Laeliinae being from what you call qualitative differences. Every recent change is explicitly stated to be based on interpretation of quantitative differences based on DNA. This is what every single author states in print! They are all using the same cladograms generated by Cassio.
You are making the false assumption that the people doing molecular work are in agreement about classification. Kew says the Australians are doing it wrong (splitting) and the Australians say that Kew is doing it wrong (lumping). The DNA is the same. DNA data may be more conservative than morphological change - may be - but is open to as many interpretations as there are people involved.
You can program a computer to generate a genus of 100species or 100 monotypic genera based on the same theoretically neutral data.
Most botanists who actually work with plants treat molecular data as one more tool - not as an absolute ignoring all else.
You also forget that for classifications to be useful they must be based on the need of the user groups. Horticulture is not the same user group as phylogenists (aka molecular systematists). Wild flower books have excellent classifications based on flowers yellow or flowers white. Home Depot has their system of "Orchid 4 inch pot" and "Orchid 6 inch pot".
Classifications are designed to present and retrieve information. Phylogeny is only one facet albeit today's 800 pound gorilla.
Eric
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08-06-2008, 08:10 PM
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Interesting. So is it safe to say that we can never have a 'standard' format for speciation, whether its based on morphological or genetic difference? Do you think that the Laeliinae classification and others will ever be settled? Is a more permenant classification system for orchids even possible in light of their highly divergent and relatively recent explosion of speciation?
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