list, but this is still under consideration. When heirloom plants are not being sold, however, laws are often more lenient. Because most heirloom plants are at least 50 years old and grown and swapped in a family or community they fall under the public domain. Another worldwide alternative is to submit heirloom seeds to a seedbank. These public repositories in turn maintain and disperse these genetics to anyone who will use them appropriately. Typically, approved uses are breeding, study, and sometimes, further distribution. US state law There are a variety of intellectual property protections and laws that are applied to heirloom seeds, which can often differ greatly between states. Plant patents are based on the Plant Patent Act of 1930, which protects plants grown from cuttings and division, while under intellectual property rights, the Plant Variety Protection Act of 1970 (PVPA) shields non-hybrid, seed-propagated plants. However, seed breeders can only shelter their variety for 20 years under PVPA. There are also a couple of exceptions under the PVPA which allow growers to cultivate, save seeds, and sell the resultant crops, and give breeders allowances to use PVPA protected varieties as starter material as long as it constitutes less than half of the breeding material. There are also seed licenses which may place restrictions on the use of seeds or trademarks that guard against the use of certain plant variety names. In 2014, the Pennsylvania Department of Agriculture caused a seed-lending library to shut down and promised to curtail any similar efforts in the state. The lending library, hosted by a town library, allowed gardeners to "check out" a package of open-pollinated seed, and "return" seeds kept from the crop grown from those seeds. The Department of Agriculture said that this activity raises the possibility of "agro-terrorism", and that a Seed Act of 2004 requires the library staff to test each seed packet for germination rate and whether the seed was true to type. In 2016 the department reversed this decision, and clarified that seed libraries and non-commercial seed exchanges are not subject to the requirements of the Seed Act. Future As the effects of climate change intensify and the world population rises, more attention is being put on heirloom plants as a way to restore genetic diversity and feed a growing population while safeguarding the food supply of diverse regions. Specific heirloom plants are often selected, saved, and planted again