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.

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