Part of a flower calyx (5)
I believe the answer is:
sepal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">part of a flower calyx</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for sepal that I've seen before include "Lapse about part of a flower" , "Green part that forms a flower's calyx" , "Part of a flower - peals (anag)" , "Part of a flower casing" , "Part of a flowering plant" .)