. "Alismatales" . . . . . . "Potamogeton ogdenii Hellquist and Hilton" . . "Liliopsida" . "Magnoliophyta" . "Potamogetonaceae" . . "Ogden's Pondweed" . "Plantae" . . . "Potamogeton" . "Hellquist and Hilton" . . . "Potamogeton ogdenii" . . .