Identification: Request: Photos of Coastal Douglas-Fir Seeds

Discussion in 'Pacific Northwest Native Plants' started by reificationofmyth, Sep 3, 2022.

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  1. reificationofmyth

    reificationofmyth New Member

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    Hello, UBC.

    IMG_2133.JPG
    I am wondering whether any of you living on the West Coast (BC to California) have photos of coastal Douglas-fir seeds. Are they all dark and matte? Would it be possible to get images of seeds? I find that you can get images of bark, needles, and cones quite easily--but the same cannot be said for seeds.

    First off, I have chosen seeds that best represent the general characteristics of each. The dark seeds are from the coastal subtype on Vancouver Island. The second photo is of just the coastal seeds in water before I planted them; note the long pen-tip-like ends not present after germination.
    The lighter-coloured seeds are from my local DF in Southern Ontario (USDA z5b), and these four seeds correspond to the two distinct looks you find around here: the two on their own are from the blue with reflexed bracts; the two below the coastal seeds are from the green with appressed bracts. I assume my local blue variety to be glauca (New Mexico area) and green to be caesia (Interior BC area). There is the possibility that the local green type is coastal, but owing to the growing zone and seed colour similarity to the blue, I am doubtful.

    I have asked previously as to the subtype of a local DF, but have recently noticed the difference in the seeds from the coastal ones I purchased. It's tricky to distinguish caesia from coastal due to similarity in needle colour and bracts, but having read that subtype can be distinguished by seed shape and colour, I am wondering whether this is the method by which to do so. (Size is different, yes, but with younger trees growing in harsh conditions one cannot expect even a CDF to be over 100 feet.)

    Thanks,
    reificationofmyth
     

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  2. Ron B

    Ron B Paragon of Plants 10 Years

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    Within the context of Pseudotsuga menziesii the caesia name is considered a synonym of glauca.

    Pseudotsuga menziesii subsp. caesia | Plants of the World Online | Kew Science

    The works mentioned here may have something relevant to your pursuit:

    I don't know of any other species that has been so widely recognized as unique and readily distinguishable, yet has held so many names. An extremely complex nomenclatural controversy surrounded this species from 1800 to 1950; for a detailed recounting of this controversy, see Reveal [n.d.]; for an even more detailed account see Hermann (1982).

    Pseudotsuga menziesii (Douglas-fir) description (conifers.org)
     
    Last edited: Sep 3, 2022
  3. reificationofmyth

    reificationofmyth New Member

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    Hello, Ron.

    Yes, I have seen caesia used as a synonym for glauca. I admit, the distinction between caesia and glauca is arguable.

    Although I am not a professional, in my opinion, I find the separation of interior Douglas-fir into caesia and glauca useful. This is due to the separate, albeit both interior, ranges of the two subspecies. (*Updated, my original link was not great. Apologies. This one makes the point clearer.) Section 4 - Douglas-Fir (Pseudotsuga menziesii) . From said link: "The varieties differ in many morphological, physiological and ecological characteristics. The coastal variety has greenish needles and longer seed cones with straight, appressed bracts, whereas the interior variety has bluish-green needles and shorter cones with reflexed bracts. Although the differences are not always obvious, strong differentiation of these varieties has been confirmed with isozymes, and nuclear, mitochondrial, and chloroplast DNA studies (Li and Adams 1989; Aagaard et al. 1995, 1998a, 1998b; Klumpp 1999; Nelsonet al. 2003). Some of these studies have also indicated strong differentiation between the northern and southern subgroups of P. menziesii var. glauca. Literature particularly from Europe (e.g. Göhre 1958; Klumpp 1999) sometimes recognizes another interior variety for the northern half of the continental range, P. menziesii var. caesia (Schwerin) Franco."

    Many publications where the distinction is made are European. Perhaps this is because said publications are older and separation into three subspecies has become obsolete?
    The attached image is a screenshot of a map from "A Study of Variability in Certain Douglas-Fir Populations In British Columbia" by Frank Ferenc Tusko. (Feel free to ask me to delete said image if it violates some policy, but the paper is a download and not a link, so this seems easier.) It is a paper from the open library UBC. Here, the distinction is again made, and in the first example, better described for my purposes.

    1, page 10:
    "Rehder (1940) summarized the characteristics of the three varieties as follows:

    Pseudotsuga taxifolia viridis (Schwer.) Aschers & Graebn.
    (as var.). It is a taller tree, with young branches spreading, larger green leaves, larger cones with upright and accumbent bracts".

    "Pseudotsuga taxifolia caesia (Schwer.) Aschers & Graebn.
    (as var.). Leaves bluuish green". Usually mentioned as a transition form between viridis and glauca.

    "Pseudotsuga taxifolia var. glauca (Mayr.) Schneid. is the Rocky Mountain form. Tree of slower growth and more compact habit, with ascending young branches: leaves shorter and more or less bluishgreen: cone about 5 cm. long, with spreading or finally reflexed bracts".

    2, page 17:
    "The separation of Douglas-fir into different varieties however, is still an unsettled question. According to Garman (1953) the "glauca" variety does not occur in British Columbia. The Interior type is sometimes identified in Europe by the variatal name "caesia". In contrast, Native Trees of Canada (1956)names the Interior form Pseudotsuga taxifolia(Poir) Britt., var. glauca (Mayr.)Sudw."




     

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  4. wcutler

    wcutler Paragon of Plants Forums Moderator VCBF Cherry Scout 10 Years

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    I am posting my one photo in case it's of any help. I posted it on the forums at Pseudotsuga menziesii subsp. glauca | UBC Botanical Garden Forums, where there was some discussion about the format of the name, but not about the ID, except that Ron B noted that it is a grafted cultivar, so maybe not useful for your purposes.
    Somehow I learned that the tree came from the Specimen Trees nursery labelled "Pseudotsuga menziesii ssp. glauca", no cultivar name given, so no more info there.
     
  5. reificationofmyth

    reificationofmyth New Member

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    Hello, Wendy.

    Thank you for the photos! I find the distinction is convenient for me because, if one believes caesia to be a "transition form" between viridis (coastal) and glauca, then 85mm cones like these--which one might assume to be coastal due to size and bracts--are easier to explain in z5b.
    One also cannot forget the puzzle of the contents of those cones. Seeds from cones that look exactly like the glauca photos you have are similar to the attached, when, according to the paper by Tusko, "The most recent contribution to our knowledge of the morphological variations is that of Allen (1960) who found significant differences between the seeds of Coastal and Interior Douglas-fir. He found that the tip of the Coastal seed is longer and more pointed. In addition it is contracted just behind the extreme tip in contrast to that from the Interior where the tip is blunter, shorter, and less contracted." There is also mention of seed colour, which I am currently unable to locate.
     

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