Clasping leaf pondweeds

Pond Weeds

Potamogeton richardsonii and Potamogeton praelongus:

Clasping leaf pondweeds

Potamogeton richardsonii (Benn.) Rydb.; Clasping leaf pondweed, Richardson pondweed.

Potamogeton praelongus Wulfen: Clasping leaf pondweed, whitestem pondweed. Potamogetonaceae (pondweed family). 

Native perennials. These submersed species have similar traits, but differ in size. They each have only one type of leaf, and lack differentiated surface/floating leaves. In both, the alternate, stalkless leaves have wide leaf bases that clasp or wrap almost completely around the stem. In P. richardsonii the leaves are 0.8 - 3.5 in (2 - 9 cm) long, in P. praelongus they are significantly larger, 4 - 16 in (10 - 40 cm) in length. Leaves are spear-shaped, broader at the base and pointed at the tip, and smooth-edged (compare to P. crispus which has teeth along leaf margins). The leaf tips of P. praelongus are cupped or hollowed, and the tip splits if pressure is applied to flatten it. Its stems become whitish and angled at the nodes, looking zig-zag. Papery, frail stipules occur in both, being much longer in P. praelongus. Flower spikes are held at or above surface, with flower stalks about the same thickness as the stems. P. praelongus is usually found in deep water with P. richardsonii growing closer to the shore.