A disseminule is a plant part that can be carried away or dispersed from the mother plant and become the source of a new plant somewhere else. It is important to be able to recognize these disseminules and their taxon identities in order to prevent their unwanted spread within or among countries. The intentional and unintentional transport of plants and plant parts across the world due to human activity is widespread. This transport has resulted in the naturalization of many species to regions outside of their native ranges. Many of these species are strongly competitive, enabling them to become invasive in their new habitats. The establishment and proliferation of invasive weeds causes huge agricultural losses and extensive destruction to the environment, here in the United States and throughout the world.
Officials in the United States Department of Agriculture (USDA) have determined that certain species not native to the U.S. are at risk of becoming invasive should they enter this country. As part of its effort to prevent the introduction of invasive or potentially invasive weeds, the USDA maintains an official list of "federal noxious weeds" (FNW) (7 CFR 360.200 and 361.6). Many taxa on this list are currently serious weeds elsewhere in the world, and about two-thirds of the taxa are currently found in the U.S. The list includes terrestrial, aquatic, and parasitic plants. Most of the FNW taxa are angiosperms, but a few are ferns and one is a green alga. Importation or transport across state lines of the FNW taxa is prohibited.
Fruits and seeds are the plant disseminules most responsible for the spread of weeds to new regions. These disseminules are frequently intercepted at U.S. ports of entry by quarantine officials, commonly as contaminants in commercial seed stocks, spices, foodstuffs, on trucks and containers, and in baggage. This tool, Federal Noxious Weed Disseminules of the U.S. (FNWD), was developed to enable accurate identification of FNW disseminules and to assemble a set of high-quality images of the disseminules of all the FNW taxa. The tool and its identification keys were designed to be used by officials at U.S. ports responsible for identification of plant pests. It may also be a useful resource for seed professionals and anyone else with an interest in, or a need to know about, the U.S. federal noxious weeds and what their disseminules look like.