five native species of Potomagetonaceae (pondweeds) in two genera. These are
moderately common rooted aquatics mostly of freshwater (but
occasionally occurring in brackish ponds). The foliage of most
species is submerged, but may extend above water level. The leaves
are alternate one elongated, branched stems (except below an
inflorescence, where they are opposite) and often straplike. The
inflorescence is a terminal spike with inconspicuous flowers.