Flow of runs stemmed by southern side (6)
I believe the answer is:
stream
'flow' is the definition.
(I know that flow can be written as stream)
'runs stemmed by southern side' is the wordplay.
I cannot quite see how this works, but
'runs' could be 'r' (cricket abbreviation) and 'r' is found in the answer.
'southern' could be 's' (abbreviation) and 's' is found within the answer.
'side' could be 'team' (a side is a sporting team) and 'team' is present in the remaining letters.
This accounts for all the letters.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for stream that I've seen before include "Brook, burn" , "Flock" , "not taken in mixed-ability group" , "'Brook, runnel (6)'" , "flower" .)