Undeveloped seed (5)
I believe the answer is:
ovule
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">undeveloped seed</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ovule that I've seen before include "Part of seed plants" , "Part of flower" , "Immature ovum" , "Undeveloped seed" , "Small plant structure that develops into a seed" .)