Awl-leaf Lilaea, Awl-leaf Arrow-grass, Flowering Quillwort: Triglochin scilloides (Synonyms: Lilaea scilloides, Lilaea subulata)
Graceful Arrowgrass, Graceful Arrow-grass, Slender Arrowgrass, Slender Arrow-grass: Triglochin concinna (Synonyms: Triglochin concinna var. concinna, Triglochin concinna var. debilis, Trigloghin concinnum, Triglochin concinnum var. concinnum, Triglochin concinnum var. debile, Triglochin debilis, Triglochin elata)
Seaside Arrowgrass, Seaside Arrow-grass: Triglochin maritima (Synonyms: Triglochin elata, Triglochin maritimum)
Marsh Arrowgrass, Marsh Arrow-grass: Triglochin palustris (Synonym: Triglochin palustre) - Not naturalized.
Three-ribbed Arrowgrass: Triglochin striata