Botanical illustration from a book by
O. V. Tome Flora von Deutschland, Österreich und der Schweiz , 1885
The upright stalk is uniformly leafy, weak, easily moved by water, 25-150 cm tall.
The leaves are alternate, without tongues, linear, solid, whole-marginal, 5-15 mm wide, bottom with a sharp protruding keel. The longitudinal veins are light, translucent, and the transverse jumpers are dark.
The inflorescence is usually shortened, devoid of normally developed leaves, branching, consists of 1–4 close spherical heads of stamen flowers and 10–20 sessile (or stalked) heads of pistillate flowers. The heads of pistil flowers are up to 20 mm in diameter. Flowers are same-sex, immersed in water, float on the surface or raised above the water. Perianth consists of 5-6 small dense dark scaly leaflets . Three stamens, one pistil. The stigma is much longer than the column . Flowering in the European part of Russia in June - July.
The fruits , which together form rigid, spiky spherical heads, are green, later darkening, pyramidal, turning sharply into the nose at the top, located on the stem. Their length is 5-10 mm, width is 3-6 mm. Fruiting in the European part of Russia in July - August.
The narrow-leaved commonweed is common in North Africa , in the temperate zone in Europe and Asia . Naturalized in Australia .
It is widely found in Russia throughout the entire European part, including in the North Caucasus , and in the southern half of Siberia , reaching in the east of the Irkutsk region [2] .
It grows in shallow water or along the banks of lakes and rivers, along meadow marshes, as well as in drainage ditches, ditches and quarries .
Propagated and spread by seeds .
It is represented by several subspecies , often elevated to the rank of a species, differing mainly in the shape and size of the fruit [2] .