Achene

Achene, also Achenium and Akene. (Gk. ἀ, a, priv. + χαίνειν, chainein, to gape). A seed-like fruit such as is characteristic of the great family of Compositæ, to which belong sunflowers, thistles, dandelions, etc. The pits of the strawberry and the small fruits forming a head in the centre of a buttercup are also achenes. The seed-like appearance arises from the fact that the wall of the seed-vessel hardens and invests the solitary seed so closely as to seem like an outer coat. See Fruit.