The origin of botany? (4)
I believe the answer is:
root
'the origin' is the definition.
('root' can be a synonym of 'origin')
'of botany?' is the wordplay.
I cannot really understand how this works, but
'of' could be 'o' and 'o' is found in the answer.
The remaining letters 'rot' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for root that I've seen before include "Underground part of a plant" , "Part of plant drawing nutrients from soil" , "support" , "Derivation" , "Rhizome" .)