This is the 15th year of continuous daily publication for 365Caws. All things considered, it's likely it will be the last year as it is becoming increasingly difficult for me to find interesting material. However, I hope that I may have inspired someone to a greater curiosity about the natural world with my natural history posts, or encouraged a novice weaver or needleworker. If so, I've done what I set out to do.
Friday, January 10, 2020
Physcia Adscendens
Day 89: Well, I can't count this one as a life-list species because I was introduced to it on a field trip with Katherine Glew, but it was the first specimen of Physcia adscendens I've found on my own. It's recognizable by helmet-shaped lobe tips as well as having "eyelashes," and although you can't tell from the photo, it is quite small. The lobes are under half a millimeter wide, and the whole lichen does not exceed two centimeters in diameter. How did I find it? When I am out shopping as I was today, I always try to park next to a tree so I can find my car again. Cars are so hard to identify! Most of them are silver-grey in colour, and 99% of them have four black tires, white lights in the front and red ones in the back. I do not have a Field Guide to Common Vehicles, and since I don't usually carry my GPS when I go in town, I frequently spend an inordinate amount of time studying license plates in the hopes of coming across the distinguishing feature which sets mine apart from the others. And yes, I have tried to get into one belonging to someone else. Fortunately, there were no consequences attached to that event. On the other hand, a tree is something I will recognize, even from a distance. I pulled up to a small ornamental which was lavishly covered in green and gold lichens. "Xanthoria!" I said, "But what's the grey-green stuff? That's not a Parmelia." I took the main photo in the composite above and then broke off two small pieces in different stages of development. I sat for a few minutes in the car examining them before driving away just in case I needed a larger sample, and that was when I discovered the "eyelashes." Thinking back on recent finds, I assumed Parmotrema, but when I got home and put the specimens under magnification, I realized I was off base. Eventually, having gone forward and backward through several dichotomous keys in both Brodo and McCune, I narrowed it down to two choices: Physcia adscendens or P. tenella. The shape of the soredia-bearing lobe tips and absence of apothecia clinched it: adscendens, predictably the more common of the two. I'll never forget that tree now, even if I can't remember where I put my car or if the person I just spoke to had a moustache or wore glasses. Priorities. You just gotta keep 'em straight.
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