Mushrooms, eg (5)
I believe the answer is:
fungi
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mushrooms eg</span>' is the definition.<br/ ><span class="explanation-format__explanation">(mushroom is a kind of fungus)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for fungi that I've seen before include "rusts?" , "Eg, moulds, mushrooms" , "provides penicillin, etc" , "Plants like mushrooms and toadstools" , "Maybe moulds" .)