Flower:

Short, head-like cluster held above or below the surface of the water, only about ¼ inch (6 mm) long, arising from some leaf axils on branching stems. Spikes have 2 or 3 whorls of flowers, each flower with a 4-parted style surrounded by 4 stamens, each stamen with a green to brownish, ladle-shaped, sepal-like appendage.

Leaves and stems:

Leaves are all submersed and more or less spirally arranged along the stem; no floating leaves are produced. Blades are flexible, usually light green to olive or sometimes reddish, linear, ½ to 3¼ inches (to 8.2 cm) long, .3 to 2.3 mm wide, pointed at the tip, toothless, not wavy along the edges. The midvein is prominent and usually flanked by 1 pair of lateral veins, occasionally none or 2; 1 or 2 narrow rows of large, empty cells (known as the lacunar band) may be along the midvein but are usually absent.

Leaf bases are stalkless, not clasping, and rarely have a pair of glands at the node. At the base of the leaf is a pale, membranous appendage (stipule), not connected to the leaf blade, often rolled around the stem with overlapping edges (convolute), blunt at the tip, not usually shredding, less than 1 inch (to 22 mm) long, greenish to brown, rarely white. Stems are slightly compressed and may frequently branch. Vegetative buds (turions), also known as winter buds, are narrowly cylindric, develop later in the summer at branch tips or some leaf axils, but are uncommon.

Fruit:

Fruit is a dry seed (achene), olive to brown when mature.

Achenes are irregularly oval to nearly round, 1.5 to 2.7 mm long with a prominent, knobby keel along the back edge. The beak is erect, .2 to .6 mm long.

Notes:

Leafy Pondweed is common throughout Minnesota, usually found in the quiet or slow-flowing waters of lakes, ponds and rivers, usually with a sandy, mucky or silty bottom and in less than 4 feet of water.

This is one of several Pondweeds with no floating leaves and linear, submersed leaves, the widest between 1 and 4 mm wide, but is the only one in Minnesota that lacks glands at the leaf nodes, has pointed leaf tips, and achenes have a prominent, knobby keel. There are 2 recognized subspecies: subsp. fibrillosus is an uncommon western species with stipules that shred into fibers, frequently has glands at leaf nodes, achenes have a less prominent keel and beak shorter than .2 mm; subsp. foliosus is found across North America and is as described above.