Request acceptable - one may get a flower (7)
I believe the answer is:
begonia
'flower' is the definition.
(begonia is a kind of flower)
'request acceptable one may get a' is the wordplay.
'request' becomes 'beg' (begging is a kind of requesting).
'acceptable one may' becomes 'oni' (I can't explain this - if you can you should give a lot more credence to this answer).
'get' says to put letters next to each other.
'beg'+'oni'+'a'='BEGONIA'
Can you help me to learn more?
(Other definitions for begonia that I've seen before include "colourful flower" , "Herbaceous plant whose flowers have no petals" , "bloomer" , "Common garden plant" , "Tropical plant" .)