Family plant? (4)
I believe the answer is:
tree
This clue is a double definition.
'family' is the first definition.
(I've seen this in another clue)
'plant?' is the second definition.
(I know that tree is a type of plant)
(Other definitions for tree that I've seen before include "Christmas decoration" , "Branching diagram" , "Root-and-branch plant?" , "Large shrub with branches" , "Genealogist's graphic" .)