shoreweed

shoreweed

(ˈʃɔːˌwiːd)
n
(Plants) a tufty aquatic perennial, Littorella uniflora, of the plantain family, that forms underwater mats but usually flowers only on muddy margins
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014