Leafy plant (4)
I believe the answer is:
fern
'leafy plant' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for fern that I've seen before include "Tracheophyte plant" , "It has feathery or leafy fronds" , "A frond is its leaf" , "Leafy plant" , "Flowerless plant with feathery fronds" .)