Grow rapidly (8)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grow rapidly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for mushroom that I've seen before include "Pinkish-brown colour" , "grow quickly" , "Increase with remarkable rapidity" , "Snowball; fungus" , "expand rapidly" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">grow rapidly</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for burgeon that I've seen before include "Grow, rapidly increase" , "bud" , "Shoot" , "sprout" , "Produce buds - flourish" .)