<p>Scientific Name: Chlorociboria aeruginascens (Nyl.) Kan.
Common Name: Green Stain
Certainty: positive notes (<a rel="nofollow" class="external free" href="http://bornnaturalist.org/notes/20060702#6">http://bornnaturalist.org/notes/20060702#6</a>)
Location: Southern Appalachians; Smokies; Cataloochee
</p><p><br></p>
Stained rotten wood.  This omnipresent green stain is due to the mycelia of a microscopic mushroom.  The next photo in the "weird stuff" set is a close-up of the fruiting body.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/7147684@N03">Jason Hollinger</a>
CC BY 2.0
<a href="//commons.wikimedia.org/wiki/Flickr" class="mw-redirect" title="Flickr">Flickr</a>: <a rel="nofollow" class="external text" href="https://www.flickr.com/photos/7147684@N03/1037424287">Green Stain</a>