Northern Prairie Wildlife Research Center
References:
Bogin, C. 1955. Revision of the genus Sagittaria. Mem. New York Bot.
Gard. 9:179-223.
Wooten, J. W. 1973. Taxonomy of seven species of Sagittaria from
eastern North America. Brittonia 25:64-74.
| Lead | Characteristic | Go To |
| 1 | Blades of emersed leaves not sagittate, lacking basal lobes or some occasionally with small caudal lobes. | Lead 2 |
| 1 | Blades of emersed leaves mostly or all sagittate, the basal lobes prominent. | Lead 3 |
| 2 | Female flowers and fruiting heads apparently sessile on the scape. | S. rigida |
| 2 | Female flowers and fruiting heads obviously pedicellate | S. graminea |
| 3 | Sepals appressed to the fruiting heads; pedicels of fruiting heads inflated; plants annual, lacking rhizomes. | S. calycina |
| 3 | Sepals reflexed on fruiting heads; pedicels of fruiting heads slender; plants perennial, with rhizomes. | Lead 4 |
| 4 | Floral bracts acute to obtuse, mostly less than 1 cm long; achene beak projecting horizontally from the apex of the achene. | S. latifolia |
| 4 | Floral bracts acute to acuminate or attenuate, usually more than 1 cm long; achene beak erect or oblique to recurved-ascending. | Lead 5 |
| 5 | Achene beak short, erect, 0.1-0.4 mm long; ventral wing of achene usually convex below the beak; basal lobes of leaf mostly shorter than the terminal one. | S. cuneata |
| 5 | Achene beak prominent, oblique to recurved-ascending, 0.5 mm or more long; ventral wing of the achene straight below the beak; basal lobes of leaf usually equaling or longer than the terminal one. | S. brevirostra |