Descent of leaf with a tear in it (9)
I believe the answer is:
parentage
'descent' is the definition.
(I know that descent can be written as parentage)
'leaf with a tear in it' is the wordplay.
'leaf' becomes 'page' (page is a kind of leaf).
'with' means one lot of letters goes inside another.
'tear' becomes 'rent' (synonyms).
'in it' is an insertion indicator.
'page' going around 'a' is 'paage'.
'paage' enclosing 'rent' is 'PARENTAGE'.
'of' is the link.
(Other definitions for parentage that I've seen before include "child-minders" , "results from birth" , "Family origins" , "Who's your father (and mother)?" , "Extraction, descent" .)