Fruit from elder plant reportedly (5)
I believe the answer is:
berry
'fruit' is the definition.
(berry is a kind of fruit)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for berry that I've seen before include "Small juicy fruit" , "eg Chuck or Halle" , "'One might be straw, rasp or blue, say (5)'" , "Word linking black or blue" , "Smal pulpy fruit" .)