Identification: Variety of Alder

Discussion in 'Pacific Northwest Native Plants' started by DavidB52, Nov 15, 2021.

  1. DavidB52

    DavidB52 Active Member

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    My neighbor has an Alder tree that is always dropping branches and seeds in our yard and I've never thought much of it before. But now that I've learned it's a nitrogen-fixing tree, I went outside today to collect some seeds. Broken branches and little cones seem to fall everywhere! Especially after the period of rain and wind we've had over the past few days.

    Now I'm trying to identify the variety of Alder it is. Attached is a photo of the cones and a couple leaves I picked up this morning. The tree itself is a real tree, not a shrub, almost as tall as the cedars growing around it.

    Can anybody here identify this variety of Alder? (Or do I have to wait until Spring and look at the male catkins?)
     

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  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Red Alder Alnus rubra.
     
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  3. DavidB52

    DavidB52 Active Member

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    Hi, Michael.

    Thanks for the quick response.

    I am curious: what identifies it as a Red Alder?
    I was looking for a curl of the leaves, but didn't see it.
    How is it different from, say, Black Alder?
     
  4. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Black Alder has round leaves, very distinctive. The other species in BC (Thinleaf Alder, Sitka Alder) have smaller seed catkins ("cones") and less clearly lobulate leaves.

    The curled-down edge of Red Alder leaves is very hard to see, really needs a magnifying glass (and isn't always present, either).
     
  5. Kurt Schneider

    Kurt Schneider Member

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    Don't forget green alder too. :) But yes, its a red alder. :)
     
  6. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Sitka Alder (Alnus alnobetula subsp. sinuata, syn. A. viridis subsp. sinuata) is a subspecies of Green Alder :-)
     
  7. Kurt Schneider

    Kurt Schneider Member

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    True. Though most guide / ref. books list them separately, and they're (in my own experience) usually treated as separate species. Hence I pointed it out. :P (Us plant nerds gotta have fun somehow, right?)
     
  8. DavidB52

    DavidB52 Active Member

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    I came across another type of Alder tree.
    This one is quite a bit smaller than the other ones.
    It has white bark and its leaves are tiny compared to the other Alders I have come across.
    What kind of Alder tree is this?
     

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  9. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Silver Birch (Betula pendula) - not an alder at all! Same family (Betulaceae), though, so related. In BC, an introduced ornamental tree; native here in Europe.
     
  10. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Aye, but if treated as a separate species (as Alnus sinuata), then Green Alder (Alnus alnobetula, sensu stricto) doesn't occur in BC ;-)
     
  11. DavidB52

    DavidB52 Active Member

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    I'd like to collect seeds from a variety of Alder trees--but I'd like to be certain of the variety.

    Anybody in these forums, in the Vancouver/Coquitlam area, know where Alder trees of the following cultivars can be found?

    Black Alder
    Grey Alder
    Green Alder
     
  12. Ron B

    Ron B Paragon of Plants 10 Years

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    You're listing common names for wild species rather than horticultural selections (cultivars). All the more so because you want precise identification of the seed sources identify which ones you are looking for by their botanical names to get the desired result.
     
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  13. DavidB52

    DavidB52 Active Member

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    Black Alder: Alnus glutinosa
    Grey Alder: Alnus incana
    Green Alder: Alnus alnobetula
     

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