An aggregate fruit or etaerio (//) is a fruit that develops from the merger of several ovaries that were separated in a single flower. In contrast, a simple fruit develops from one ovary, and a multiple fruit develops from multiple flowers. In languages other than English, the meanings of "aggregate" and "multiple" fruit are reversed, so that "aggregate" fruits merge several flowers. The differences in meaning are due to a reversal in the terminology by John Lindley, which has been followed by most English-language authors.
Not all flowers with multiple ovaries form aggregate fruit; the ovaries of some flowers do not become tightly joined to make a larger fruit. As a result, many fruits form which are commonly mistaken to be of the aggregate variety. Aggregate fruits may also be accessory fruits, in which parts of the flower other than the ovary become fleshy and form part of the fruit.
The individual parts of an aggregate fruit come in many forms. Common examples are:
- Multiple fruit, a structure formed from the ovaries of several flowers, that can resemble an aggregate fruit
- Compound fruit, a term sometimes used when it is not clear whether a fruit is an aggregate fruit, a multiple fruit, or a simple fruit formed from a compound ovary
- Accessory fruit, a fruit in which some of the flesh is derived from tissue exterior to the carpel
- Carpel, the "building blocks" of the ovary
- "Define Etaerio at Dictionary.com". Retrieved 2015-01-17.
- Hickey, M.; King, C. (2001). The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press.
- Spjut, R.; Thieret, J. (1989). "Confusion between multiple and aggregate fruits". The Botanical Review. 55 (1): 53–72. doi:10.1007/bf02868781. S2CID 24994626.
- Beentje, H.; Williamson, J. (2010). The Kew Plant Glossary: an Illustrated Dictionary of Plant Terms. Royal Botanic Gardens, Kew: Kew Publishing.
- Janick, J.; Paull, R.E. (2008). The Encyclopedia of Fruit and Nuts. CABI. ISBN 9780851996387.