Isoetes lacustris var. paupercula Isoetes flettii Isoetes paupercula Isoetes piperi Isoetes echinospora var. flettii Isoetes echinospora f. flettii Isoetes howellii var. piperi Isoetes maritima var. flettii Isoetes occidentalis var. piperi Isoetes lacustris subsp. paupercula Isoetes echinospora subsp. flettii
World Flora Online, http://www.worldfloraonline.org/, accessed June 20, 2024