#umbrina

  Trentepohlia umbrina, high up in the Mt. airy valley black walnut, Cincinnati, Ohio.

I see three pretty common lichens on this tree but I was not actually trying to photograph any of these despite getting some good shots of one Lecanora hybocarpa complex lichen. aka bumpy rim lichen. Which I actually wanted to use as scale for the size of what I really wanted to take pics of.

Instead I was trying to photograph this beautiful red streak because I feel like often it is over looked and under appreciated from a botanical and mycological perspective, often even assumed to be part of woody material on red oaks as cork or lenticil tissue.

There is a niche group of semi complex crack species and exposed surface species of filimentous algae, actinomycetes, and cyanobacteria that make up a good portion of tree bark biota that we don’t often get taught about despite many of them being directly associated as a functional group(photobiont) of many lichen species. In this case, subaerial algae is the noted or deamed group type, this one on Black Walnut bark high up in the canopy is a filimentous chlorophyte...

 https://www.researchgate.net/figure/Examples-of-subaerial-habitats-and-algae-on-and-in-plants-A-Thin-film-of-green-algae_fig15_280577788

specifically the carotenoid rich Trentepohlia spp., Most species of Trentepohlia species are generalistic, even pollip clustering or forming long elongated hairs that are free standing and grow on rocks and trees freely depending on moisture and mineral contents. Some are directly associated with parasitism or within’ lichen as a mutualist coevolved as photobiont. 

Most species are pretty dang hard to Identify, resulting in utilizing microscopy or sequencing in order to resolve a taxa delineation.

Here, pictured above, is a very small species of bark dwelling caespitose (mat forming) relatively as prostrate as possible( growing non erect and almost adhering to the surface.) The good ol’ fashion algae is easy to get a sample of and put under a scope free floating in water, once done look at the filimentous grouping, linear psuedoseptae with elongated cells in conjunction with the roles of plasmodesmata for cytoplasmic streaming is not what I saw, instead I got adjacent rounded blobs forming the filamentous line with most of the pigment filing the cells. So matted dark red tree balls is what I viewed, Trentepohilia umbrina. The interesting thing is that this species is very small and while preferring exposure/barren niche like many Trentepohilia spp. do; we see this species in shaded cracks and crevices more than in zones of full exposure. Hence why umbrina may have been selected as epithet. ( within the shadows)

The most common species and easiest to ID are:

Trentepohlia abietina ( a small polip cluster forming tree only species) often associated with elongated cell structure. (https://www.jstor.org/stable/44841106)

Trentepohlia aurea Orange rock hair (the only species with an english common name that I am aware of) most of the other species only seem to have dutch, norwegian , russian, siberian, or native american first nation (inuit, metis, Musqueam, Squamish, and Tsleil-Waututh) names. This species is huge and easy to see the hairy polip clusters.

Trentepohlia jolithus , a true nordic and beringian species limited to high volcanic regions in the northern hemisphere and very bright and prostrate forming dense mats on rocks appearing as a film

  Trentepohlia umbrina , or as I call it, matted on bark dark red tree balls clustered as a filamentous line, https://www.inaturalist.org/taxa/410587-Trentepohlia-umbrina/browse_photos  This is what you see under obs scope, If you

Other common species but with no accessibility as far as ID delineation are these:

Trentepohlia flava , a coastal salt mist generalist species often found along the western coast of North America on rocks but also commonly found in europe near sea side areas in the north, while this doesn’t fully explain it’s locality niche or fix any range maps because we really don’t know if it has a cosmopolitain range or not and already a var. complex has formed along with range divisions.

https://www.proquest.com/openview/7f3a8e73a75fb8212470443aa189452c/1?pq-origsite=gscholar&cbl=37953.