#acarospora

Acarospora robiniae

My brother was sending me pictures of his hike in Arizona this weekend, being like "is this a good lichen?" "is this a good lichen?" "what lichen is this?" and I wanted to be annoyed because he's my brother, but I was just so thrilled someone was engaging me in my interest! He sent me lots of pictures of what I presumed were A. socialis, but upon further investigation, some of those could have been sister species A. robiniae? Likely not since it has a more costal distribution, but it looks like a few inland samples have been collected. This electric-yellow crustose lichen grows in areolate patches up to 5 cm wide on volcanic rock. It has a waxy, lumpy texture, and is pitted with immersed, punctiform apothecia. A. robiniae can be distinguished from A. socialis by the former's brighter color, yellow apothecial disks, and its broader areole attachment points. Just like I did when going through my brother's pictures, a lot of folks just see bright yellow lichen and don't look any closer, assuming it's A. socialis, and so A. robiniae has probably gone overlooked throughout its range in California and Mexico, and its range may even extend into Arizona.

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Acarospora strigata

Acarospora veronensi

Acarospora heufleriana

Acarospora thelococcoides

Soil eyes lichen

The sleepy-tireds are hitting me hard at the moment. I am gonna need at least 2 more cups of tea if I plan to get through this work day. And while I wait for that to kick in, allow me to tell you a little bit about my good pal, A. thelococcoides here. This crustose lichen has a warty thallus that grows in patches up to 10 cm across on granite-rich, undisturbed, arid soils in California and northern Mexico. It has a greenish-brown thallus often covered in a thick layer of chalky-white pruina. Each wart-like projections is usually topped by an immersed apothecium with a dark-brown to black disc surrounded by a thick, white-gray pruinose rim. Like a bunch a little eyeballs staring up at you and judging you for disturbing its previously undisturbed habitat. How dare you?

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Acarospora strigata

Hoary cobblestone lichen, grooved cobblestone lichen

*tired sigh* sooo look. What is a species? The concept of a species is already kinda arbitrary, and it's not easily defined--particularly not between the major kingdoms of life. And this is difficult enough in species that have more "notable" physiological distinctions, but gets trickier in organisms like lichens, where differences aren't easily noticed. Keeping all that in mind, meet what is like a complex of multiple species, A. strigata. This crustose lichen is a specialist of "harsh microhabitats," and grows on exposed limestone and granite in Asia, Africa, Europe, and the Americas (though keep in mind that this range may expand/contract with further investigation). It has an areolate or verruculose thallus that is brown or bluish gray, but often covered in a thick layer of pruina making it appear frosted or hoary (god I love that word). The surface is often cracked or fissured, particularly near the embedded, black-disked apothecia. Potential species vary in habitat choice, areole size and shape, surface color, and chemical production, but molecular work is needed to determine if these are variations within or between species. I wish whoever decides to travel down that road much luck, and may the lichen gods small on you.

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Acarospora bullata

Cracked lichen

Hey. . . hey buddy . . . respectfully, what the fuck? A. bullata is an areolate-subsquamulose crustose lichen that grows on mostly upland, siliceous rock in Asia, Europe, North and South America. It has rounded to angular areoles that become more elongated and fan-shaped around the margin of the thallus. Its upper surface is shiny yellow-brown, red-brown, or dark brown, and its lower surface is darker brown-black. It has round to irregular apothecia which have a lumpy disc so that they look like a bubbling little pot of baked beans (the nicest descriptor I could muster, honestly). A. bullata has a green algal photobiont, and contains gyrophoric and lecanoric acid.

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Acarospora obpallens