Form of hemp is present in half the world (10)
I believe the answer is:
hemisphere
'half the world' is the definition.
(I've seen this before)
'form of hemp is present' is the wordplay.
'form of' is an anagram indicator (the letters need to be in another 'form').
'present' becomes 'here' (both can mean in attendance).
'hemp'+'is'='hempis'
'hempis' is an anagram of 'hemisp'.
'hemisp'+'here'='HEMISPHERE'
'in' is the link.
(Other definitions for hemisphere that I've seen before include "See 6" , "covers half the world" , "Half the globe" , "part of the world" , "Cerebral division" .)