Forest plant (4)
I believe the answer is:
fern
'forest plant' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for fern that I've seen before include "Type of plant" , "Bracken, for example" , "Flowerless plant with feathery fronds" , "Feathery frond plant" , "Plant reproducing by spores" .)