<p>Drawing of <i>Agaricus ustalis</i> in "Icones selectae hymenomycetum nondum delineatorum" by E.M. Fries. 
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Description of the fungi by Fries on <a rel="nofollow" class="external text" href="http://www.e-rara.ch/zut/content/pageview/2859408">page 24</a> (in Latin).
<a href="//commons.wikimedia.org/wiki/Elias_Magnus_Fries" title="Elias Magnus Fries">Elias Magnus Fries</a>
between 1867 and 1884 <div style="display: none;">date QS:P,+1850-00-00T00:00:00Z/7,P1319,+1867-00-00T00:00:00Z/9,P1326,+1884-00-00T00:00:00Z/9</div>
<a rel="nofollow" class="external text" href="http://www.e-rara.ch/zut/content/pageview/2859421">e-rara.ch</a>