Nice photos!
I often see these dark hyphal strands on lichens, but I
usually ignore them unless I see a lot of ascomata (at least 15 or so). The
reason is that it often takes squashing quite a few until you find enough spores/asci
to work with (and you probably want some intact ascomata left after you’re
done.) The ascomata are round spots (sometimes elongate) on the hyphal strands.
You can see many of them in Richard’s awesome Arctoparmelia photo.
Lichenostigma is a good place to start. One of the
two subgenera in Lichenostigma (Lichenogramma) produces these superficial dark
hyphal strands. A common, unrelated genus, Sphaerellothecium, also produces
superficial dark hyphae. My guess is that Richard’s Thamnolia photo is one of 2
Sphaerellothecium that inhabit Thamnolia (S. thamnoliae and S. taimyricum, both
known from Washington but not the OP!) And the one on Arctoparmelia looks like Sphaerellothecium
arctoparmeliae (but should be verified by squashing a few ascomata and measuring
some spores.) The genera Intralichen and Trimmatostroma can form brown
hyphae on lichen thalli too although they are more commonly seen as vertical
strands in the hymenia of lichen apothecia, at least Intralichen.
If using the website The Lichenicolous Fungi
of the Pacific Northwest, to match a fungus with dark hyphae to a host
lichen, pay attention to results in the genera Lichenostigma and
Sphaerellothecium. BUT keep in mind that the other Lichenostigma subgenus (the
nominate Lichenostigma) does not form these visible, superficial brown hyphae. (I
should’ve included the subgenus with these records… maybe in the next update,
but the brief descriptions mention the dark hyphae if they are visible). Our
most common species of Lichenostigma are in this subgenus, and show as dark
spots (usually conidiomata) with no interconnecting dark hyphae. The common
Lichenostigma on Usnea is L. maureri, BUT it is in the nominate subgenus and
does NOT produce visible hyphae (just dark dots on the thallus). Lichenostigma
maureri is common on shrubby lichens (mostly Alectoria, Letharia and Usnea in my
experience in the northwest).
