Have a discussion about one sort of tree (7)
I believe the answer is:
conifer
'tree' is the definition.
(conifer is a kind of tree)
'have a discussion about one sort' is the wordplay.
I cannot really understand how this works, but
'about' could be 'on' (as in a book 'on' a certain topic) and 'on' is found in the answer.
'one' could be 'i' (Roman numeral) and 'i' is located in the answer.
This may be the basis of the clue (or it may be nonsense).
'of' is the link.
Can you help me to learn more?
(Other definitions for conifer that I've seen before include "Tree such as pine, yew etc" , "Type of tree" , "E.g. yew, pine or fir" , "one branching out" , "Eg, pine, fir or cypress" .)