The stem is long, thin, evenly leafy, weak, usually thickened and bent under an inflorescence, easily moved by water.
Leaves are alternate, without tongues, linear, shortly pointed at the apex, plano-convex, whole, whole-marginal, up to 2 m long and 1-5 mm wide, noticeably tapering from the middle to the base, without veins from above, from below with a protruding middle vein.
The inflorescence is usually shortened, devoid of normally developed leaves, simple or branched, consists of 2-3 close spherical heads of stamen flowers and 1-3 sessile (or on legs) heads of pistillate flowers. Heads of pistil flowers can be located on the legs in the axils of the leaves. Covering leaves are wide-stemmed. Flowers are same-sex, immersed in water, float on the surface or raised above the water. The flowers located lower on the stem and branches are pistillate, higher on the stem are stamen. Perianth consists of 5-6 small, thin, unpainted, scaly leaflets . Three stamens, they are short, one pistil. Anthers up to 0.75 mm long. The column is long, with fruits hook-shaped bending. Flowering in the European part of Russia in June - July.
The fruits , together forming rigid, spiky spherical heads, are green, later reddish-brown to blackish, without a constriction in the middle, located on the stem. Fruiting in the European part of Russia in August.
Cowberry is common in Eurasia .
In Russia it is found mainly in the northern regions of the European part, in Eastern Siberia and the Far East (including Kamchatka ).
It grows in water or along the shores of lakes , less often in shallow rivers.
Propagated and spread by seeds .