Plants grown from seeds of Sagittaria falcata, S. lancifolia, S. platyphylla, S. rigida, S. isoetiformis and S. papillosa were grown in water-saturated soil or soil submerged to 4.5, 12, 19.5 or 27 cm. Length and width of leaves and petiole lengths were measured at anthesis of the first flower on the first inflorescence produced by each plant. In general, leaf width and length were decreased by submergence, and petiole length increased. The species × water depth interaction was significant for emersed leaf width, leaf length and petiole length except for S. lancifolia leaf length and S. papillosa leaf length and width. These trends indicate genetic differences among, and variability within, taxa. Leaf width, leaf length and petiole length of plants growing in seed source populations were measured. The means from these measurements, when compared to those from experimental plants, indicate that both groups of plants respond similarly to variations in water depth.