In other words, the flesh of the fruit develops not from the floral ovary, but from some adjacent tissue exterior to the carpel (for example, from receptacles or sepal).
[1] Accessory fruits are usually indehiscent, meaning that they do not split open to release seeds when they have reached maturity.
[11] Current research has proposed that a single class of genes may be responsible for regulating accessory fruit formation and ripening.
[12] A study using strawberries concluded that hormone signaling pathways involving gibberellic acid and auxin affect gene expression, and contribute to the initiation of accessory fruit development.
[6] Metabolic modifications in different developing accessory fruit tissues are due to the varied distributions of compounds such as triterpenoids and steroids.