Cactus Tree?????

Discussion in 'Cacti and Succulents' started by alma, Aug 10, 2008.

  1. alma

    alma Member

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    Can someone please tell me what this cactus tree is called??? I have searched and searched and to no avail. It is growing on my uncles property in San Antonio, Texas.
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  2. joclyn

    joclyn Rising Contributor

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    it's an opuntia. i have no idea which particular one, though. i'm not aware of any that grow in 'tree form' which doesn't mean they don't exist...it could just be that it's very old and has developed that pronounced trunk.

    it's lovely!
     
  3. markinwestmich

    markinwestmich Active Member

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    According to Cactiguide.com, there are 181 species in this genus. There are several upright species.

    Good luck.

    http://pick4.pick.uga.edu/mp/20q?guide=Opuntia

    This is a cool link. According to this source there are a 190 species. This is a systematic approach to identifying the plant yourself.
     
  4. Rosemarie

    Rosemarie Active Member

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  5. Cereusly Steve

    Cereusly Steve Active Member

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    The "Cactiguide" is out of date. Many of the names they list are now synonyms, hybrids or referrable to other genera. There are now fewer species remaining in Opuntia. The majority of them are now in other allied genera.

    The growth form is completely wrong for Brasiliopuntia (formerly Opuntia) brasiliensis.

    The plant is probably Opuntia elata. Its not a native species.
     
  6. Daiv

    Daiv Member

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    Steve,
    Can I ask you to tell us where you got this information? What are the other allied genara? What is the authority that has the power to relegate many of these species to synonyms or hybrids?

    Daiv
    CactiGuide.com
     
  7. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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  8. Daiv

    Daiv Member

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    Michael,
    Thank you for the link. However, if you look on that site through the Opuntia classification, most of the naming is older than the data on CactiGuide.com and the most frequent reference is Anderson's The Cactus Family, which is the same source that I decided to use.

    That said, I don't think that the site you referenced is without value. I think the more resources available, the better. But the notion that taxonomy becomes outdated like a carton of milk is rediculous. Anyone who has followed it long enough soon finds out that taxonomists continually split names apart and lump them together and split them apart again. Most of this is done based on educated opinion. Mankind does not even have a proper definition which defines what a species actually is in the first place. So I find it quite silly when anyone makes such difinitive statements about which classification system is correct and which one is outdated. I use Anderson's classification because in my OPINION, I think it is perfectly suitable. Although I even made some minor tweeks to it - including the addition of species not known at the time. Of course someone else might have their own opinion as to what classification they like better and that is fine. I'm not claiming that the system I chose is right, I'm saying that none of them are right, they ultimately are opinions.

    Additionally, with the synonym list/search feature. You can look up species under ANY name that the plant was referred to in the past. This makes the listing never out of date.

    And a final note: There is so very very little work being done on Opuntia - and I mean virtually zero work in the field - to claim that the "majority of them [Opuntia] are now in other allied genera" is absurd! I've had the pleasure of communicating with Dave Fergusson, who is the foremost Opuntia expert and it is his educated opinion that the relegation of so many Opuntias into synonyms and hybrids is completely unfounded. I tend to agree with him. Even then, I'm not going to go posting about forums telling other people that whoever doesn't follow Fergusson is outdated. How can I or anyone make that claim when nobody (and I mean nobody) knows where the line is to be drawn between species, subspecies, variety, etc.

    Ever hear of the taxonomic impediment?
     
  9. Cereusly Steve

    Cereusly Steve Active Member

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    Sorry but the USDA GRIN very much incomplete and out-of-date. The Internet won't be of much help.

    I got the info from my own reserch on Opuntia and allied genera.

    I have a listing (with references) of the currently accepted Opuntioid genera in the files of the "Opuntia and kin" group.

    http://tech.groups.yahoo.com/group/Opuntia_and_kin/

    You can use E.F. Anderson's book "The Cactus Family" as your reference but it too is out-of-date. The genus Nopalea is also now been shown to be a good genus separate from Opuntia. His synonymy for Opuntia is incorrect and many of the pix are misidentified.
     
  10. Cereusly Steve

    Cereusly Steve Active Member

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    He who dwells on chaos will never find order from it all. One often tends to wax philosophical when they have no solid evidence as proof to back up what they say. Unless you understand WHY various authors have classified certain plant genera and plant groups in a certain way, you don't understand why so many taxonomic problems exist. It all looks completely chaotic to an outsider looking in but it really isn't. Opinions don't feed the admiral's cat.

    Anderson's book was already out-of-date by the time it was published.

    The Opuntioideae are not as chaotic as you suggest.

    There has been a significant amount of research on the Opuntioid group in recent years and much as been done to show that the traditional circumscription of the genus Opuntia is polyphyletic. Rowley and Benson lumping everything into Opuntia was completely arbitrary, was done simply for convenience and was never considered a satisfactory or natural arrangement. DNA evidence has provided additional proof of that.

    I too know Dave Ferguson and his primary interest has been in the southwestern Opuntioids and most of his work still remains unpublished. It is very difficult to follow someone who has yet to publish their research.

    You should consider tracking down the many articles by Jon Rebman, Donald Pinkava and Marc Baker, all of whom have published many papers on the subject in recent years.

    There is now much cytological evidence that proves that hybridization occurs frequently in the Opuntioids and that many of the recognized species are actually of hybrid origin.

    You should also get a copy of Succulent Plant Research volume 6 (2002) for a review of the current research on the Opuntioideae and the currently accepted genera. Much more has been published since then.
     
  11. Daiv

    Daiv Member

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    Steve,
    Thank you for the link. I am going to look into this further, but on first glance the accepted genera don't seem that different than Anderson's.

    Is your own research published somewhere?

    Daiv
     
  12. Cereusly Steve

    Cereusly Steve Active Member

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    One needs to more than just glance. I based my list of genera on the same info Anderson based his plus a few he missed that are also recognized. Anderson does not provide a key to the genera. There still remains a few more problem species groups that also deserve to be separate genera also.

    I will formally publish my results when I am able.
     
  13. Daiv

    Daiv Member

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    Steve,
    Alright, now you’re talking. Much more substantial information. I'm certainly interested in the resources you have pointed out -thank you for that.

    Of course my dilemma is this: CactiGuide.com is not intended to be a scientific journal that claims the latest taxonomic breakthrough. In fact, just the opposite - I state on the onset that I use Anderson's classification because it is what I started with. And it would be maddening for me or anyone to try and include every name change that is published (and often like Fergusson and your own work - not published). And not really make it any more useful to the people who use it.

    Even so, the Linnaean classification system itself is outdated and in desperate need of a new system. As I stated elsewhere - without a clear (or even semi-clear) definition of the taxonomic ranks themselves, it is impossible to clearly define a group of living things. That is, until you can distinguish absolutely what exactly makes one thing a species and what makes it only a subspecies and so on, you are in fact only going to be dealing with opinions - even if they are educated opinions.

    "Opinions don't feed the admiral's cat." Indeed and the cat has been starving ever since man decided that he could organize living things into a tidy little system of his own design.

    Here is an interesting article on the subject of taxonomy:

    http://www.wired.com/science/discoveries/magazine/16-10/ff_barcode

    So back to CactiGuide.com - the primary objective is to help individuals ID any cactus that they might encounter. Obviously there is a lot of work to do, but nobody is giving me any grants to get it done faster. So if they can use the images and descriptions to determine that the plant they found is Opuntia salmaniana, for example, then it doesn't matter how many times the name gets changed, they'll be able to look it up by cross reference using the synonym search features. That's a far cry better than trying to seek out the opinions of a bunch of guys who may or may not have their research published in some obscure journal somewhere that the majority of the world never even heard of.

    Don't get me wrong! I'm not discounting anyone's work or the value of any publication. I think it is noble that you are working with Opuntia directly - more power to you. I am simply making the point that cactus classification is a moving target and it has been reclassified by well-meaning people over and over again since they were first discovered. To think that is going to stop any time soon is a sort of 'chronological snobbery'. And while there are a few people dedicated to the endless pursuit of taxonomic perfection, most people just want to get a name for a plant that they are growing or saw on a hike somewhere.

    Daiv
     
  14. lorax

    lorax Rising Contributor 10 Years

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    OK, aside from all the cactus controversy that's going on here, I'd put in a second for Opuntia brasilensis, or whatever it is now being called (I'm not up on my cactus taxonomy.)

    I can personally testify that a number of the Opuntias form into trees in areas where there is no winter to slow them down or kill them back; I used to live in the south of Ecuador (now in the north) and the house I was at had a 7-8 foot tree of O. ficus-indica.
     
  15. Cereusly Steve

    Cereusly Steve Active Member

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    It is still definitely NOT Brasiliopuntia (formerly Opuntia) brasiliensis. Even without seeing the flowers, the growth pattern is completely wrong for that species. For Brasiliopuntia, the main axis is indeterminant and cylindrical with whorls of lateral branches with very thin leaf-like stems. The plant in the picture has an obvious dichotomous branching pattern typical of arborescent Opuntia species. Not the same at all as Brasiliopuntia. The branching pattern has nothing to do with the age of the plant.

    The plant in the picture is most likely Opuntia elata.


    It is true that arborescent Opuntia species occur in tropical regions of the New World but the lower growing species from colder regions will not become arborescent when grown in milder climates.
     

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