Little picture of poinsettias (5)
I believe the answer is:
inset
'little picture' is the definition.
'of poinsettias' is the wordplay.
'of' indicates a hidden word.
'INSET' can be found hidden inside 'poinsettias'.
(Other definitions for inset that I've seen before include "Place within" , "Additional insert" , "Small picture within borders of another" , "Gore" , "Something put into something else" .)