akene

An akene, or achene, is a type of simple dry fruit produced by flowering plants. It is indehiscent, meaning it does not split open at maturity to release the seed. Achenes typically contain a single seed, and the seed is attached to the wall of the ovary (the pericarp) at one point by the funiculus, while the pericarp and seed coat remain distinct.

A key distinction is that an achene is a dry fruit with a single seed that does not open to release it, whereas other dry fruits may be dehiscent or have multiple seeds. Achenes should not be confused with nuts (usually larger, with a hard, woody layer), or with caryopses (grains in which the pericarp is fused to the seed coat, as in grasses). Some fruits that look like achenes can be misinterpreted in everyday language, but true achenes have the single-seed, indehiscent structure as described.

Common examples include the seeds of sunflowers (Helianthus annuus), which are technically achenes; seeds of dandelions and many members of the buttercup family; and buckwheat seeds. In the strawberry, what people commonly call seeds on the surface are actual achenes, while the red flesh is an enlarged receptacle, an example of an aggregate accessory fruit rather than a true achene.

Achenes are often dispersed by wind, animals, or water. Some species have adaptations such as a pappus or other structures that aid wind dispersal, enabling the seed to travel farther from the parent plant.