Identification: Can this really be Cedrus libani or is it C. deodara?

Discussion in 'Gymnosperms (incl. Conifers)' started by wcutler, Jun 12, 2011.

  1. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    I thought I was finally getting the hang of cedars this year, but I'm surprised by the tag on this tree at VanDusen Botanical Garden, and I'm wondering if the ID is wrong, or if not, what should I be noticing that would make me see this tree as Cedrus libani? Here's a photo of the tree in question on the right, which is tagged Cedrus libani, and a tree tagged Cedrus libani ssp. brevifolia 'Trevoro' a bit toward the background on the left, which I recognized as a Cedrus libani. In contrast with that, I thought the tree on the right was Cedrus deodara.
    20110611_VanDusen_Cedrus1andLibani_Cutler_P1130246.jpg

    I'm noticing the drooping leader(s), and bark that looks just like what I see on Wikipedia for C. deodara. I saw another C. deodara in the garden with much longer needles, but the length of these (around 3cm) still fits the description I found somewhere but have now lost.
    20110611_VanDusen_Cedrus1_Cutler_P1130256.jpg 20110611_VanDusen_Cedrus1_Cutler_P1130329.jpg
    20110611_VanDusen_Cedrus1_Cutler_P1130249.jpg 20110611_VanDusen_Cedrus1_Cutler_P1130247.jpg 20110611_VanDusen_Cedrus1_Cutler_P1130328.jpg

    Here are a few photos of the C. libani ssp. brevifolia 'Trevoro'. Maybe this cultivar is not typical of the libani, but it looked close enough for me to guess the species. I've looked for bark photos, but it doesn't seem so simple for libani, as they seem to sometimes have smooth bark, as shown here, and sometimes crevassed peely-looking bark as shown in this Wikipedia photo. I didn't see a libani bark photo that looked like the tree in question.
    20110611_VanDusen_CedrusLibani_Cutler_P1130259.jpg 20110611_VanDusen_CedrusLibani_Cutler_P1130251.jpg 20110611_VanDusen_CedrusLibani_Cutler_P1130330.jpg
     
  2. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    It does look rather like Cedrus deodara to me too, but the possibility it is a hybrid between the two needs to be considered as well (and if grown from C. libani seed pollinated by C. deodara, could explain the label). I'm not aware of any studies ever being done on the potential for cedar hybrids, but it is likely that they could exist, and would be tricky to identify.

    Bark pattern on cedars is more age-related than species-related; yours is fairly typical for a medium-young cedar (smooth, unfissured, on even younger trees). The wiki photo linked shows bark of an older tree.
     
  3. Ron B

    Ron B Paragon of Plants 10 Years

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    The one on the right looks like a Cedar-of-Lebanon to me, it is quite tabular etc. The correct spelling of the cultivar name is said to be 'Trevoron'. It's among multiple Cedrus selections originating with W. Goddard in Victoria, BC. This one was introduced to the general trade by Iseli nursery in Oregon.
     
  4. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    So not droopy enough to be deodara? It seemed too full and lush to be Cedar-of-Lebanon. I'm wondering what the "etc" is that I might have looked for to get the ID.
     
  5. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Deodar Cedar can also be quite tabular.

    A DNA test!

    Otherwise, next time it produces any cones, look to see if the scales are fairly smooth (Lebanon Cedar), or with a slight horizontal ridge (Deodar Cedar). It's a subtle difference though, not easy to see (and am not certain if it is 100% reliable).
     
  6. Ron B

    Ron B Paragon of Plants 10 Years

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    Notice that the leaders have the same orientation as the ends of the branches. Stereotypic Himalayan cedar produces arching tips, tree shown is not drooping. Tree manuals and identification handbooks address the differences. Van Dusen has a office on the way to the library where I believe you can ask about specific accessions - I have done this in the past, anyway. "For John W. Oastler" might be enough to find out the source of the specimen you are interested in. If it's from wild-collected seed that would be significant.
     
  7. M. D. Vaden

    M. D. Vaden Active Member 10 Years

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    I'll take a look for that next time I'm in an arboretum.

    Never had the need to determine one from the other out here yet, but I still find that kind of detail interesting, although I've forgotten a lot.

    Almost considering repeating the evergreen ID class at the college this winter, to renew some of the more inconspicuous things to look for.
     
  8. Ron B

    Ron B Paragon of Plants 10 Years

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    Public plantings with groupings of multiple specimens of the same species are good places to look for normal levels of variation.
     
  9. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    The difficulty is finding cedars (particularly Deodar Cedars) with cones reachable on low branches; decidedly rare. And only available as mature closed cones for a short period from late summer until they break up in autumn. But all the cones I've been able to check so far have shown the ridging (easiest to observe in the top half of the cone, and easier by feel than by eye), while Lebanon Cedars (sensu lato, including Turkish, Cyprus and Atlas) don't. The other difficulty is that cedars in cultivation may well not be representative of the full range of variation in the wild.
     
  10. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    I'm still trying to get the idea of what the difference in habit is between these two trees. In San Diego, all the trees I thought were Cedrus libani were identified as Cedrus deodara. Here's one: http://www.geographylists.com/deodar.jpg.
    What am I not understanding here? What about this should say deodara to me?

    The others were at Marston House (I didn't get a photo), and some book of trees in Balboa Park had a similar photo.
     
  11. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    Here's one that didn't come with an ID. I'd have said C. libani before I started this thread, but it looks more like C. deodara than the ones identified as that in San Diego. Does the cone indicate which?
     

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  12. Ron B

    Ron B Paragon of Plants 10 Years

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    We can't feel for ridges looking at your picture. As far as the last two trees go, with what I can see in these shots I would not be surprised if the first one was Himalayan - that would be my guess from the distance picture was taken from. Since the bottom one has thick needles it might perhaps be Mediterranean.
     
  13. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    I received a note back from Samantha Sivertz at VanDusen:
    Here are a few more photos. Both trees could have this number of needles in the clusters. Are these in the second photo pollen cones? I thought they were just very young seed cones, but now I've seen ones posted labelled pollen cones that look like that.
    20110728_VanDusen_CedrusLibani_Cutler_P1150918.jpg 20110728_VanDusen_CedrusLibani_Cutler_P1150921.jpg 20110728_VanDusen_CedrusLibani_Cutler_P1150923.jpg

    I've been trying to understand what these ridges are Michael mentioned. Here are photos from Wikimedia of the two species. The one labeled Himalayan, photo by Roman Köhler, is on the left (original source, public domain); the libani, photo by Jerzy Strzelecki, is on the right (original source, Creative Commons).
    Deodara_Roman Köhler_800px-Himalaya-Zeder-Zapfen.jpg Libani_Jerzy Strzelecki_800px-Cedars24(js).jpg
    Here's the one I could find on the VanDusen tree in question. I know Michael said it's hard to tell from a photo. Is it evident here?
    20110728_VanDusen_CedrusLibani_Cutler_P1150922.jpg
     
  14. Michael F

    Michael F Paragon of Plants Forums Moderator 10 Years

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    Pic 2 - immature pollen cones, due to open this autumn.
    Pic 3 - old pollen cone left over from last year.
    Pic 4 - can't see any ridging, because the cone is (a) a bit blurred, and (b) top facing away.
    Pic 5 - scales smooth, unridged, as normal for C. libani.
    Pic 6 - looks like it is ridged; note how the sun and shade interact at the top left and top right of the cone, with the high ridges catching the sun and shading just beneath them. Suggests probably C. deodara to me.
     
  15. Peter T

    Peter T Member

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    Hello, The form of a cedar tree can be very distracting. The pendulous branch tips or lack of them maybe due to vigour, age, growing conditions. Especially noticeable with a row of seedling grown trees. Check the leaf tips, libani are ment to have translucent points. A named nursery grown tree I have seen has finely tapered clear points and no hairs on twigs. deodars and atlantic cedars are blunter with a much shorter clear tip with hairs. All factors need to be taken into account. I have taken a interest in cedars lately due to a group of 4 in Ashbury Park, Timaru. They just dont look right. Horizontal branches, with long needles, dark bark, mature size but not that old. keys to deodar. Maybe deodar x atlantica 'Glauca'.
     

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