A fruit in which some of the flesh is formed not from the ovary but from adjacent tissue such as the hypanthium or the receptacle. Sometimes called a pseudocarp.
The Hip, is the fruit of the Rosa genus. This photo shows the hypanthium of the Dog Rose species Rosa canina before the formation of the hip.
This photo shows a hip, open to reveal the seeds. The hip consists of a red fleshy covering, derived from the hypanthium which encloses a number of yellow seeds (hairy achenes), each one formed from a single ovary.
Another example of an accessory fruit is the Strawberry in which achenes dot the outside of a fleshy fruit derived from the receptacle of the flower