Potamogeton nodosus - Long Leaf Pondweed

Long Leaf Pondweed is a fully aquatic, perennial herb with submerged rhizomes and floating leaves from erect, leafy branches. Native to America, it is now distribed worldwide, usually present and conspicuous in ponds, lakes, and rivers. The stems are branched and up to 2 m long. The leaves are of 2 types; the submersed leaves are alternate, thin, the blades linear-lanceolate or sometimes broader, 8-20 cm long and 1-3 cm wide, and have petioles 2-13 cm long. Stipules are conspicuous, brownish, and 2-7 cm long. The floating leaves sometimes appearing opposite, thickened, coriaceous, lenticular to elliptic in shape, 3-12 cm long and up to 4.5 cm wide. The inflorescence is a spike, the flowers in whorls of 10-17, on erect peduncles 3-15 cm long that arise from leaf axils. The fruits are brownish or reddish, 3.5-4.5 cm long, 2-3 cm wide and have a short, erect beak. Long Leaf Pondweed is found all over the warmer world.