Achene

An achene is a type of simple dry fruit produced by many species of flowering plants. Achenes are "monocarpellate" (formed from one carpel) and indehiscent (they do not open at maturity). Achenes contain a single seed that nearly fills the pericarp, but does not adhere to it. In many species, what we think of as the "seed" is actually an achene, a fruit containing the seed. Typical achenes are the fruits of buttercup, buckwheat, and dandelion. It is sometimes spelled "akene", and occasionally called "achenium" or "achenocarp."