Accessory Fruit

A fruit in which some of the flesh is formed not from 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. The first photo shows the hypanthium of the Dog Rose species Rosa canina before the formation of the hip. The next 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

dog rose hypanthium
dog rose hip and seeds
strawberry aches