Ingredient for baking part of plant, reportedly (5)
I believe the answer is:
flour
'ingredient' is the definition.
(flour is a kind of ingredient)
'plant reportedly' is the wordplay.
'plant' becomes 'flower' (flower is a kind of plant).
'reportedly' indicates a 'sounds like' (homophone) clue.
'flower' sounds like 'FLOUR'.
'for baking part of' is the link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for flour that I've seen before include "Main ingredient of bread" , "Finely ground grain" , "It;s made from grinding cereal grain" , "Cake ingredient" , "Wheat powder" .)