Plate shaped like flower part (5)
I believe the answer is:
petal
'flower part' is the definition.
(I know that perianth is a is part of flower)
'plate shaped' is the wordplay.
'shaped' indicates anagramming the letters.
'plate' is an anagram of 'PETAL'.
'like' is the link.
(Other definitions for petal that I've seen before include "Leapt (anag.)" , "Plate (anag.)" , "Leaf-like part of flower head" , "Part of flag" , "Part of a flowers corolla" .)