Myriophyllum sibiricum

Perennial, submerged, herbaceous aquatic plant.

50–100 cm.

The stem is pale yellow, flaccid, hook-shaped at the base and incrassate below an inflorescence and pale yellow. At the nodes, there are short solitary tubercles between the leaf bases and on the margins of the leaf base. The turions are distinct, dense, and the leaves are short- and broad-lobed.

The sessile leaves are arranged in whorls. The lamina is pinnately lobed. The whorls consist of four or occasionally three leaves. The leaves are 1.5–3 cm long, blue-green, with 4–10(–15) pairs of lobes. The lobes are far apart, often moderately long, thick and rigid.

The rather erect inflorescence is emerged above the water surface. The flowers are arranged in whorls, sessile, small and unisexual. There are four floral leaves in floral whorl. The staminate flowers are above the pistillate flowers. The bracts are shorter than the flowers and serrate.

The fruit is a schizocarp with drupe-like mericarps.