re: cocklebur and burdock

Discussion in 'Plants: Nomenclature and Taxonomy' started by Elaynna, Aug 15, 2013.

  1. Elaynna

    Elaynna New Member

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    sometimes I see cocklebur and burdock used as one and the same. I also have come across a plant called Agrimony (Agrimonia eupatoria) that also goes by the name Church steeples and cocklebur.

    now, is Agrimony also cocklebur and also burdock? I don't think it is.

    Can anyone give me the latin and family names of both cocklebur and burdock, if they are not the same and if they also are not Agrimony.

    Thanks very much!

    Elaynna
     
  2. Daniel Mosquin

    Daniel Mosquin Renowned Contributor UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    In North America, burdock usually refers to members of the genus Arctium (Asteraceae) while cocklebur usually refers to members of Xanthium (Asteraceae). I've never heard of cocklebur being used for Agrimonia (Rosaceae) until you mentioned it, though I do see some sites using that. But, these are common names, and perhaps they are used regionally or locally as such.
     
  3. Elaynna

    Elaynna New Member

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    ok thanks very much. I have one other question. Sometimes I see an herb under a family name in one book, but, in another book it will acknowledge that it was of that family name, but, now, it is in another family. Why are the family names being changed? It can get confusing especially if I'm using an older book.
     
  4. Daniel Mosquin

    Daniel Mosquin Renowned Contributor UBC Botanical Garden Forums Administrator Forums Moderator 10 Years

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    That's a hard one to explain briefly, but I'll try.

    Plant names, including families, are intended to both group and classify as well as reflect evolutionary relationships. As the understanding of evolutionary relationships changes (especially with recent techniques like analyzing DNA), there is a knock-on effect on how plants are grouped and classified.

    For example, if a scientist discovers that all the species in family A are actually more closely related to some of the species in family B than are other species in family B, then all of the species in family A will move in to B. This might look something like this:

    Family A:
    --Species 1
    --Species 2
    --Species 3

    Family B:
    --Species 4
    --Species 5
    --Species 6

    Then evidence is uncovered that suggests Species 1, 2, and 3 are closely related to species 5...

    Family A: dropped

    Family B:
    --Species 4
    ----Species 5
    ----Species 1
    ----Species 2
    ----Species 3
    --Species 6

    That's an oversimplification, but I hope it at least explains the principle.

    And, for an entirely different reason, plant families (and the species placed in them) may change based on who first validly published and described the plant family. This is pretty rare these days, but if you are looking at older books it may have affected them. What happens here is that someone, say, in France in 1823 publishes a family name based on a particular grouping of species. This finds its way into common use for 150 years until someone in 1973 uncovers that someone from Germany in 1821 had made a different family name for the group (and validly so). Because of the principles of priority (whoever published it first validly), the species should then get reassigned to the 1821 name (unless there is a general agreement among taxonomists to use the 1823 name because switching would cause too much confusion...).

    Anyway, those are a couple reasons. If you search for "why do plant names change" in a search engine, you'll probably find a few more.
     
  5. Elaynna

    Elaynna New Member

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    ok thanks very much. It does help clear up some confusion.

    Elaynna
     

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