<p>Scientific Name: <i>Agaricus diminutivus</i>
Common Name: Diminutive Agaricus
Certainty: sure of genus (<a rel="nofollow" class="external text" href="http://bornnaturalist.org/notes/20060610#21">notes</a>)
Location: Southern Appalachians; Smokies; CabinCove
Date: 20060610
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Close-up of gills, at 30x.  Note the dk brown "beads" -- cystidia?  [No, I'm fairly sure those are spores, probably in groups of 4 still attached to the basidia.  All told each "bead" is probably only 20-30 microns wide, but this is definitely visible at 30x magnification.  In rare cases you can actually make out the individual spores in cute little diamond configurations, but not here.]
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/7147684@N03">Jason Hollinger</a>
CC BY 2.0
<p><a rel="nofollow" class="external text" href="https://www.flickr.com/photos/7147684@N03/1052184916/">Diminutive Agaricus</a>
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<ul><li>Uploaded by <a href="//commons.wikimedia.org/wiki/User:Amada44" title="User:Amada44">Amada44</a></li></ul>