Photo © Pete and Noe Woods, all rights reserved
Pittsburgh, Pennsylvania, United States (Google, OSM) Details Hide details


Air pollution extirpated most of this genus of lichens from Pennsylvania about a hundred years ago. So why it was growing in Frick Park, in the middle of Pittsburgh, the air pollution capitol of the east, I do not know.

It was growing on an ash tree, attached to the trunk where the trunk was about 3 inches wide. The lichen clump is about 4 inches wide, with the longest branch about 4 inches long. The tree was infested with emerald ash borer, and had been recently cut down.

This may be an isolated waif, or it may be part of a larger population. I still have to do a better search of the immediate area, and of other ash trees around the park, to see if there are any other colonies.

The elastic cord inside each stem clearly identifies this as an Usnea. There are 9 species of this genus historically known from Pennsylvania; I haven't yet figured out which species this is or if any other Usneas have been collected in recent decades.

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Comments & Identifications

Posted by pete_woods about 5 years ago (Flag)
beard lichens - Photo (c) Arthur Chapman, some rights reserved (CC BY-NC-SA)
ctracey's ID: beard lichens (Genus Usnea)
Posted by ctracey almost 4 years ago (Flag)

I have also noticed this pattern. Usnea growing on ash dead trees that have fallen to the ground from EAB. I try to look at ash trees whenever they fall, in the city, and about 1 out of 3 downed trees that I have looked at have a single Usnea growing on the grown. This in contrast to an abundance of other macrolichen Genera like:
Parmotrema (less common)

out at Moraine and a few other places I come across Usnea. I recently found one at Keystone SP. But they are always a good find.

Posted by bdolney over 1 year ago (Flag)

This is probably U. strigosa, but U. mutabilis can look similar. Its proximity to the city may be the reason it doesnt bare apothecium like many other specimens do.

Posted by tcurtis 9 months ago (Flag)
Posted by johnplischke 7 days ago (Flag)
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beard lichens - Photo (c) Arthur Chapman, some rights reserved (CC BY-NC-SA)
Community ID: beard lichens (Genus Usnea)
ctracey johnplischke 2 people agree
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Observation © Pete Woods
Cc by nc small some rights reserved
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