365Caws is now in its 14th year of publication, and was originally intended to end after 365 days. It has sometimes been difficult for me to find new material, particularly during the winter months, but now as I enter my own twilight years, I cannot guarantee that I will be able to provide daily posts. It is my hope that along the way I may have inspired someone to a greater curiosity about the natural world. If so, I can rest, content in the knowledge that my work here has been done.
Friday, December 15, 2017
Needs TLC
Day 63: Backspace, readjust. Bruce McCune's marvelous books have sent me back a couple of steps, and now I need to unlearn what I thought was Placopsis gelida. This bull's-eye lichen is most likely Placopsis lambii instead. Gelida is a more northern species, although given the 2800' elevation location where this specimen occurs, it could be either. McCune recommends TLC to make the distinction, i.e., Thin-Layer Chromatography. In the absence of access to TLC, he further recommends classifying any morphologically identical examples as Placopsis lambii, the identification which is most likely to be correct.
Y'know, lichenology has gotten a whole lot more complicated with the advent of technology. The same issues are occuring with the classification of vascular plants. Arnie and I were just talking about this earlier in the week. He is of the mind that classification by morphological similarities makes field identification much easier, and he's correct. However, just because a plant looks like another plant, it doesn't follow that they are necessarily related (or conversely, two plants with very different appearances may in fact be connected genetically). I argued that the new taxonomy creates a better understanding of the plants in question even though it's confusing, but then Arnie pointed out that much of the genetic research is only being done on specific sections of the total DNA profile. A different lab looking at a different section might make a different determination for the relationship with other species. There are times when I just want to throw my hands in the air and go back to calling things what I learned them as originally, a left-brain/right-brain argument which in the end, the right brain usually wins. After all, I'm a scientist.
Labels:
botany,
bull's-eye lichen,
genetics,
Placopsis lambii,
taxonomy
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