Brain cells working to discover wild flower (10)
I believe the answer is:
cranesbill
'wild flower' is the definition.
(I've seen this before)
'brain cells working' is the wordplay.
'working' indicates an anagram.
'brain'+'cells'='braincells'
'braincells' with letters rearranged gives 'CRANESBILL'.
'to discover' acts as a link.
(Other definitions for cranesbill that I've seen before include "Herb Robert" , "wild flower" .)