Placopsis Let's-Call-It Lambii

Day 155: There is a good bit of debate over whether this particular Placopsis lichen should be P. gelida or P. lambii. Some sources claim that P. gelida has not been found in Washington, and that herbarium records labelled as such are actually misidentifications of P. lambii. Others will tell you that P. gelida is the most common species of Bull's-eye Lichen from Alaska to California. Who do you believe? And why can't they nail it down? The simple answer (and trust me, the alternative is much more complex) is that sufficient genetic analysis of the samples has not been done. Gene sequencing is a fairly new tool for the lichenologist's toy box, and obviously, there's a substantial backlog of research to be done. As lichen DNA is examined, we are having to split genera, create new taxonomy, and to reevaluate what we thought we knew. Science is not a static field (no pun intended, but I'll leave it there for your enjoyment). It is always changing, always evolving as technology progresses and allows us to take a closer look.

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.