About Sparganium emersum Rehmann
Sparganium emersum Rehmann is a species of flowering plant in the cat-tail family, commonly called European bur-reed and unbranched bur-reed. It has a circumboreal distribution, found across the northern latitudes of Eurasia and North America. This is an aquatic plant that grows in shallow water bodies including ponds and streams, and can occasionally grow to become very abundant. It is a perennial herb that forms a floating stem reaching up to 2 meters in length. Its leaves may either be limp and floating, or stiff and erect, extending above the surface of the water. The leaves are flat and straplike, and sometimes have a triangular, keeled base; this feature can be used to distinguish it from the similar species Sparganium angustifolium. The species is monoecious, meaning each individual plant produces both male and female inflorescences. Both types of inflorescence are spherical: the male inflorescence is a ball of stamens, while the female inflorescence is a ball of developing fruits that grows below the male spheres.
