Tree resin rising in lime leaf (5)
I believe the answer is:
elemi
'tree resin' is the definition.
(I've seen this before)
'rising in lime leaf' is the wordplay.
'rising' shows that the letters should be reversed in order (in a down clue, letters go up).
'in' indicates a hidden word.
'imele' is hidden within 'lime leaf'.
'imele' back-to-front is 'ELEMI'.
(Other definitions for elemi that I've seen before include "Resinous stuff" , "Fragrant resin used as incense - Emile (anag)" , "Extract" , "Fragrant substance" , "Oleoresin" .)