Quarter thus includes area for grass (7)
I believe the answer is:
esparto
'grass' is the definition.
(I've seen this before)
'quarter thus includes area' is the wordplay.
'quarter' becomes 'e'.
'thus' becomes 'so' (synonyms).
'includes' means one lot of letters goes inside another.
'area' becomes 'part' (eg an area or part of a city).
'so' enclosing 'part' is 'sparto'.
'e'+'sparto'='ESPARTO'
'for' acts as a link.
(Other definitions for esparto that I've seen before include "Tough, coarse grass" , "Grass used in making rope" , "A poster (anag.)" , "Source of paper" , "Grass, used for ropes, paper" .)