I’m Lichen It! Day One

After pointing out that the deluge had brought out a green covering to the big tree in the back yard, and after foolishly referring to it as “moss,” I’ve been told that it’s more likely to be “lichen.” My thanks to my high school friend James on FaceBook (dude, do you realize that it’s been almost fifty years?!) and Jemima Pett here for the information!

The sunny side of the tree. No lichen (or moss) seen.

This is what I thought ALL of the bark looked like until earlier this week.

Rough texture, but… brown. (BTW, if anyone can help me identify what kind of tree this is I would appreciate it. I’ve tried a couple of those “plant ID” apps but they’ve just said, “Huh? What? Moi?”)

The green color of the lichen on the shady side is still obvious, but the color has started to fade from when it was soaked. I did find this article from the US Forest Service, which has a line that indicates that my initial guess might not be totally out of left field when I speculated about the color change and appearance being “activated” by the rain.

When a lichen is dry, its color is usually gray or colored like the fungal cells on the upper cortex. When a lichen is wet, those cells become transparent, and the algal cells underneath get a chance to show their vibrancy.

Green algae generally give the lichen a bright green color when wet…

I wonder how much of the color difference might be due to lighting and how the iPhone’s camera sensor tries to “help” by making some processing decisions with the raw data.

I also wonder about the “fruiting bodies” that Jemima asked about. I tried doing a Google image search for “lichen fruiting body images” – that was a mistake. I got one or two lichen pictures and hundreds of rather graphic and disturbing images of a skin condition called “lichen planus.” 🤮🤢

However, on closer examination of the green spots above…