Comment: Thanks Jason for your feedback :)

re: X. chlorochroa: I totally agree about the possibility that it is X. chlorochroa, the primary distinguishing morphological features listed in Lichens of North America (Brodo), Macrolichens of the Rocky Mountains (McCune and Goward) and Macrolichens of the Pacific NW (McCune and Geiser) and “Key to Xanthoparmelia in North America, Extracted from World Keys of Hale 1990” (Thomson 1993) include 1) lobe width (X. chlorochroa lobe width is generally > 1.5mm; X. wyomingica lobe width is generally < 2mm wide), and 2) the degree the the margin incurls. Brodo additionally places attachement to substrate as a defining characteristic, while McCune and Goward and McCune and Geiser do not

I did some remeasuring and picked out a larger sample size and measured at more areas along the lobe, not including branching points; the lobes are more 1.2 – 3.5 mm which puts it definately more towards X. Chlorochroa, however X. chlorochroa is described by Brodo (but not Hale) as having a pale brown underside, which this one has a black when dry and chocolate brown when wet underside, as well as the margins are not as incurled, which may not be as important since as you said that research shows the habit seems to be very variable in the species, and the deree to incurling may be related to its degree of attachment to the substrate – no need to incurl to a large degree if its not moving about.

re: Molecular Phylogentics and Evolution: abstract seems to also indicate that the current species groupings for Xanthoparmelia are incorrect, the morphological distinctions that have delineated the current species don’t neatly overlap with the genetic clusters at species level (if I am interpreting the abstract correctly). Maybe you’re right, Jason, that this is an example of where habit traits are more variable, not a distinguisher of species.

Maybe its Xanthoparmelia chlorochroa, and if that turns out to be right I get to add a new species to the list for Turnbull! :) Currently there’s only X. mexicana, X. digitiformis and X. wyomingica on their list.

re: Black fungus, it definately could be filaments, that would make sense, unless its conidioforms of some sort? That could be possible, yes? The black cuts extend into and through the upper cortex, does the L. cosmopolites do the same? I’m still looking for areas that have the neat mycelial forking pattern of the Lichenostigma cosmopolites. The pattern I’m finding looks more like splotchy necrosis of the upper and lower cortex along with a few long black thick cuts that do not fork, maybe a similar species as L. cosmopolites or the same species, just at a different stage of development or in different environmental conditions? Super neat that Xanthoparmelias have a specific parasite! Thanks Jason!