An Achene is a small and thin-walled one-seeded dry indehiscent fruit. It is a common fruit type and is the one most likely to be mistaken for an (a chunky) seed, given that it is nothing more than a seed along with an additional thin covering, the “pericarp” (or the ovary wall). It is the fruit type of the two biggest plant families, which are the sedge family (Cyperaceae) and the aster family (Asteraceae), and is found in several other families too.