Grasslands (4)
'grasslands' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for plains that I've seen before include "Large areas of level country" , "Large areas of flat lands" , "Flats" , "Extensive tracts of level open land" , "Large tracts of level open land" .)
(Other definitions for pampas that I've seen before include "South American prairie" , "Prairies (with grass)" , "Argentinian plains" , "Argentina grassy plain" , "Grassy plains of Argentine" .)
'grasslands' is the definition.
(lea is a kind of grassland)
This is all the clue.
(Other definitions for leas that I've seen before include "in which flowers might be found" , "meadows" , "Arable or pasture lands" , "Fields suitable for grazing by livestock" .)