This came to the attention of Medford-based botanist George E. Davenport, who decided to bring seeds and live plants to his friend Minor Pratt, in Concord. He and Pratt seeded a pond near the Sudbury River, and he suspected Pratt of conducting additional distributions. As early as 1879, concern was voiced by botanist Charles Sprague Sargent, director of Boston's Arnold Arboretum, that this non-native species threatened to become a nuisance, based on dense growths reported in Cambridge. Davenport confessed in an entry in the Bulletin of the Torrey Botanical Club, Vol. 6, page 352: "I have several times had plants of Trapa natans that were collected in the vicinity of Boston, during the present year, brought to me for identification, and I have entertained no doubt as to the manner of its introduction into waters outside Cambridge Botanic Garden. But that so fine a plant as this, with its handsome leafy rosettes and edible nuts, which would, if common, be as attractive to boys as hickory nuts now are, can ever become a 'nuisance' I can scarcely believe." Water caltrop has been declared an invasive species from Vermont to Virginia, and is classified as a noxious weed in Florida, North Carolina, and Washington. As of 2020, both T. natans and T. bicornis have been reported growing wild in the waterways of the United States. In Australia and its state of New South Wales water caltrop has been declared a noxious weed. Legality of sale and shipment in the United States In 1956 T. natans was banned for sale or shipment in the United States, subject to a fine and/or imprisonment. This law was repealed by HR133 (116th United States Congress (2019–2020)) on December 27, 2020. Role in fasciolopsiasis transmission Fasciolopsiasis is an ailment resulting from infection by the trematode Fasciolopsis buski, an intestinal fluke of humans, endemic in China, Taiwan, Southeast Asia, Indonesia, Malaysia, and India; this fluke can be transmitted via the surfaces of these and other water plants. During the metacercarial stage in their lifecycle, the larval flukes leave their water snail hosts, and swim away to form cysts on the surfaces of water plants, including the leaves and fruit of water caltrops. If infected water plants are consumed raw or undercooked, the flukes can infect pigs, humans, and other animals. Uses The fruits are edible raw or cooked, and the seeds can be eaten as well. It