Heather taken from fell in Gloucestershire (4)
I believe the answer is:
ling
'heather' is the definition.
(I've seen this before)
'taken from fell in gloucestershire' is the wordplay.
'taken from' indicates the answer is hidden within the clue.
'LING' can be found hidden inside 'fell in gloucestershire'.
(Other definitions for ling that I've seen before include "Swimmer" , "Burbot" , "Slender food fish" , "Heather - fish" , "Cod-like fish" .)