An aggregate fruit develops from several separate carpels of a single flower, producing a collection of individual fruit units. The number of original flowers is crucial: a multiple fruit involves several flowers, whereas an aggregate fruit starts with one.[ref]
Glossary of Botanical Terms by PlantNET. Aggregate-fruit examples and Figure18V–Z: aggregate versus multiple arrangements
A strawberry makes the arrangement tangible. Its surface bears numerous achenes, each an individual dry fruit, supported by the enlarged fleshy receptacle. The familiar edible object therefore combines many fruit units with tissue outside the individual ovaries.[ref]
Genome-scale transcriptomic insights into early-stage fruit development in woodland strawberry Fragaria vesca by Chunying Kang and others. Abstract and Introduction: separate achenes on the enlarged receptacle
For a simple counting example, a single flower with twenty separate fertile carpels could produce twenty fruit units in one aggregate if each develops successfully. The count follows the separate carpels, not twenty separate flowers. Aggregate fruit and accessory fruit consequently describe different properties: the former concerns the collection of units, while the latter concerns contributions from non-ovarian tissue.
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