Expand mushroom breed (8)
I believe the answer is:
multiply
This clue could be a double definition.
'expand mushroom' is the first definition.
'multiply' can be an answer for 'expand' (thesaurus). I am not sure about the 'mushroom' bit.
'breed' is the second definition.
(I know that breed is a kind of multiply)
Can you help me to learn more?
(Other definitions for multiply that I've seen before include "in several ways, each with its own stress" , "Reproduce" , "Accumulate" , "Add an amount to itself a number of times" , "Increase the number" .)