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Angraecum didieri & rutenbergianum

Discussion in 'Orchid Species' started by DaveH_SF, Jun 14, 2015.

  1. DaveH_SF

    DaveH_SF Member

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    San Francisco
    I have A. didieri and A. rutenbergianum blooming at the same time. I can't see any difference at all between them. Other than a small difference in temperature tolerance (rutenbergianum goes cooler), what difference is there?

    The first picture is didieri, and the second is rutenbergianum.

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    piotrm and RadioFreeKirkwood like this.
  2. Marni

    Marni Well-Known Member Staff Member Supporting Member

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    Santa Rosa, CA
    I have come to believe that the main difference between the species in this section is the labeling. If you compare the keys for didieri, rutenbergianum and elephantinum everything overlaps which makes it very subjective.
  3. gg68

    gg68 Angraecoid addict

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    France, Alsace
    It is always really hard to see a difference between these two species,
    especially since they are crossed in culture for years to obtain rounder and whiter flowers...

    In your case, I would have say that the first one, the one you called "didieri", is in a fact more a rutenbergianum and the second one looks more like a didieri, especially because of its leaves shape!!

    If you want to see a real difference you have to see some "original" orchids blooming, blooming in Madagascar or coming from Madagascar!!
  4. GaryYG

    GaryYG Active Member

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    Brisbane, Queensland, Australia
    Going by John Hermans [2017] both of these seem to me to be Angraecum rutenbergianum. Johan says that Angcm. rutenbergianum is one of the most common angraecums in cultivation.

    Angcm. rutenbergianum is a short-stemmed plant and produces pure white flowers that have a broadly elliptic lip, just like the two photographs.

    Angcm. didieri is a long-stemmed plant with short leaves up to 5 cm long. It bears smaller pure white flowers that have a more oblong, broader lip.

    The other confusing species mentioned by Marni is Angcm. elephantinum. This is a short-stemmed plant with 4-7 leaves that are 7.5-10 cm long and 18-25 mm wide. It carries large blooms that have ivory to greenish-white sepals and petals and a pure white lip that has a greenish-white 8.5-13 cm long spur. The lip is elliptic-oblong with an acute-acuminate apex.

    Reference: Hermans, J. (2017) "The Angraecum Conundrums. "Lindleyana in Orchids, 86 (6):448-457.