An achene (also sometimes referred to as "akene" and occasionally "achenium" or "achenocarp") is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and (they don't open at maturity). Achenes contain a single seed that nearly fills the pericarp, but doesn't adhere to it. In many species, what we think of as the "seed" is actually an achene, a fruit containing the seed. Examples Typical achenes are the fruits of buttercup,… (More on Achenes)