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
APA Division of Clinical Neuropsychology later conference at Houston, Texas, where Division 40 was represented along with other neuropsychology-related organizations, produced the formal criteria for training and education in the field. Division 40 was one of the sponsoring organizations of the Houston conference. Division 40 has evolved over time, forming four advisory committees on science, education, practice and public interest, mirroring the overall structure of the APA. It is one of the three largest divisions of the APA. The division had 636 members in 1981, 1785 members in 1985, 3880 in 1995, and 4348 in 1998. Currently it has around 5000 members, indicative of growth