Area on African flower not quite indigo (4)
I believe the answer is:
anil
'indigo' is the definition.
(anil is a kind of indigo)
'area on african flower not quite' is the wordplay.
'area' becomes 'a' (maths abbreviation).
'on' is a charade indicator (letters next to each other) (in a down clue, letters appear on others).
'african flower' becomes 'nile' (I've seen this in another clue).
'not quite' means to remove the last letter (most but not all of the word).
'nile' with its last letter taken off is 'nil'.
'a'+'nil'='ANIL'
(Other definitions for anil that I've seen before include "Indigo (plant or dye)" , "name of man" , "Dye for nail" , "It produces dye" , "A blue dye" .)