The clue is:
Grass over pretty Cambridge backs
The answer is RYE. I get the grass part, but what is the connection in the rest of the clue? This is from the Saturday Telegraph Cryptic, clue no. 29562
"Grass" is the definition of the answer.
"Over pretty Cambridge backs" is the wordplay, in which "backs" means "last letters of the preceding words."
R from "over" + Y from "pretty" + E from "Cambridge" = RYE, a type of grass.