akènes

An akène is a type of simple dry fruit that develops from a single carpel and contains a single seed. The fruit wall, or pericarp, is thin and does not split open at maturity to release the seed. Instead, the pericarp remains attached to the seed. This characteristic distinguishes akènes from other dry fruits like legumes or capsules.

Akènes are commonly found in many plant families, including the Asteraceae (sunflower family), Ranunculaceae (buttercup family), and Polygonaceae (knotweed family). Familiar examples include the fruits of sunflowers, dandelions, strawberries, and clematis. In strawberries, the fleshy red part is not the fruit itself, but rather an enlarged receptacle; the true fruits are the small, achene-like structures on the surface.

The structure of an akène is typically small and often features appendages that aid in dispersal. These can include wings, bristles, or hairs. For instance, the "fluffy" parachute-like structure of a dandelion is made up of modified sepals (called a pappus) attached to the akène, facilitating wind dispersal. The hard outer layer of an akène protects the enclosed seed during dispersal and until germination conditions are met. Their simple structure and effective dispersal mechanisms contribute to the widespread success of plants that produce them.