Habitat: Both clasping-leaf pondweeds grow in the submersed plant community. They grow in many types of sediments to depths of up to 4 meters.
Description: Both species have long, branching stems that are rounded in cross-section (1 to 2.5 mm in diameter), emerging from a spreading rhizome. The submerged leaves are alternately arranged, oval to lance-shaped, and clasp the stem with a lobed base. No floating leaves are produced. Fruiting stalks emerge from leaf axils toward the end of the growing season. Clusters of small fruits form in a spike toward the tip. Each fruit is disk-like with an erect beak-like protrusion. The leaves help to distinguish the two species. The leaves of P. richardsonii are 3 to 12 cm long with wavy edges, and 13 to 21 veins (some more prominent than others). The more fibrous portions of the stipules persist in the
leaf axils, leaving stiff tufts. The bases of the leaves clasp one-half to threequarters of the way around the stem. The leaves of P. perfoliatus are generally smaller (1 to 5 cm long) with 7 to 15 veins. The stipules
(which only occur on the upper portion of the stem) disintegrate without a trace fairly early in the growing season. The leaf bases clasp all of the way around the stem. |
