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
Naked short selling a price rise. In 2008, the SEC banned what it called "abusive naked short selling" in the United States, as well as some other jurisdictions, as a method of driving down share prices. Failing to deliver shares is legal under certain circumstances, and naked short selling is not "per se" illegal. In the United States, naked short selling is covered by various SEC regulations which prohibit the practice. Critics, including Overstock.com's Patrick M. Byrne, have advocated for stricter regulations against naked short selling. In 2005, "Regulation SHO" was enacted; requiring that broker-dealers have grounds to believe that shares will be