Emblem of South Africa: river within a river with drink (6)
I believe the answer is:
protea
'emblem of south africa' is the definition.
(national flower of South Africa)
'river within a river with drink' is the wordplay.
'river' becomes 'r' (abbreviation).
'within' is an insertion indicator.
'a river' becomes 'Po' (Italian river).
'with' is a charade indicator (letters next to each other).
'drink' becomes 'tea' (tea is a drink).
'r' inserted into 'po' is 'pro'.
'pro'+'tea'='PROTEA'
(Other definitions for protea that I've seen before include "South African plant" , "S.African flowering shrub" , "Ascend" , "S. African shrub; to pear (anag.)" , "South African evergreen" .)