Triglochin's a genus in the family Juncaginaceae containing around 18 species. North America has four (or five) species, two of which can also be found in the British Isles (and Europe): Triglochin palustris (marsh arrowgrass) and Triglochin maritimum (sea arrowgrass). Australia has many more. The most widely used common name for the genus's arrowgrass, although it should be noted that these plants aren't really grasses. Many of the common names for species make use of the term arrowgrass, alth… (More on Triglochin)