Seed are sometimes sold commercially while still enclosed within the hard wall of the fruit, which must be split open to reach the seed. Different groups of plants have other modifications, the so-called stone fruits (such as the peach) have a hardened fruit layer (the endocarp) fused to and surrounding the actual seed. Nuts are the one-seeded, hard-shelled fruit of some plants with an indehiscent seed, such as an acorn or hazelnut. Seeds are produced in several related groups of plants, and their manner of production distinguishes the angiosperms ("enclosed seeds") from the gymnosperms ("naked seeds"). Angiosperm seeds are produced in
7 Seeds are listed below. A main topic of "7 Seeds" are the four seasons, since every team is named after one of them: Spring, Summer A/B, Autumn and Winter. The team members were chosen into their teams based on which seasons their names matched best. Almost every "7 Seeds" chapter arc is named after one of the 24 solar terms consisting of the 72 pentads (Shichijūni kō). The Rainwater chapter, for example, completely consists of Shichijūni kō. "7 Seeds" is written and illustrated by Yumi Tamura and published by Shogakukan. It began serialization in the November 2001 issue of the monthly