| Family | Scientific Name | Common Name | Habitat | Distribution | Image |
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| Juncaginaceae | Triglochin maritima | Northern Arrowgrass | Brackish coastal habitats and inland bogs. | Circumboreal, south in North America to NJ, OH, NE, NM, Mexico (BCN, BCS, CHH, MEX); also Patagonia. Reports from DE and MD are based on misidentifications; no specimen could be located for Bucks County, PA. | 
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| Juncaginaceae | Triglochin palustris | Slender Arrowgrass | Marshes, rich fens, alkaline meadows and shores. | A circumboreal species, south in America to ME, NY, nw. PA (Erie County; S. Grund, pers. comm., 2023), s. OH, c. IN, c. IL, IA, NE, NM, AZ, CA, Mexico, and South America. | 
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| Juncaginaceae | Triglochin striata | Southern Arrowgrass | Brackish to nearly freshwater marshes. | The species has an extensive range, occurring in tropical Central and South America, West Indies, Africa, and Australia; in North America, it ranges from MD and DE (extirpated) south to s. FL and west to LA, and also on the west coast in CA and OR. | 
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