A more thorough explanation:

A mortmain statute is a law that limits gifts and other dispositions of land to corporations, especially charitable ones. It also prohibits corporations from holding land in perpetuity.

For example, in England, laws such as the Provisions of Westminster and Magna Carta required the Crown's authorization before land could vest in a corporation. The purpose was to prevent lands from being held by religious corporations in perpetuity. This type of restriction influenced the enactment of certain state laws in the United States that restrict the amount of property that a corporation can hold for religious or charitable purposes.

Another example is a state law that limits the amount of land a non-profit organization can own. This law is designed to prevent non-profit organizations from accumulating too much land and becoming too powerful.

In summary, a mortmain statute is a law that limits the amount of land that a corporation, especially a charitable one, can own and prohibits them from holding land in perpetuity.