Succulent core of plant supplied (5)
I believe the answer is:
agave
'succulent' is the definition.
(I've seen this before)
'core of plant supplied' is the wordplay.
'core of' indicates the central letters.
'supplied' becomes 'gave' (giving is a kind of supplying).
The middle of 'plant' is 'a'.
'a'+'gave'='AGAVE'
(Other definitions for agave that I've seen before include "Succulent; daughter of Cadmus" , "Plant, source of sisal" , "plant in Mexico" , "source of tequila" , "native growing up in tropical America" .)