Oedogonium is a genus of filamentous, free-living green algae. It was first discovered in the fresh waters of Poland in 1860 by W. Hilse, and later given its name by German scientist K. E. Hirn.
The morphology of Oedogonium is unique, with an interior and exterior that function differently from one another and change throughout its life cycle. These protists reside in freshwater ecosystems in both hemispheres and are both benthic and planktonic in nature.[3][4][5][6][7] They form algal patches on the water's surface and so interact closely with a multitude of other algae.[8] These filamentous cells' life cycles include both sexual and asexual reproduction, depending on the life cycle stage.
Although quite common, Oedogonium is difficult to identify since key definitive markers are only present during reproduction, which is an uncommon life stage among this genus.[9] Oedogonium has been found to be important in the fixation of heavy metals in freshwater ecosystems.[10][11]
First named Oedogoniaceen (in German), the name Oedogoniales is derived from the Latin oedos (meaning swelling or tumor) and gonos (meaning offspring or seed). This name describes the morphology that Hirn witnessed during Oedogonium sexual and asexual reproduction and later described in his publication, “Monographie und iconographie der Oedogoniaceen."[12]
Oedogonium species were first reported in the late 19th century by Hilse (1860),[13] Gołowin (1964),[14] Kirchner (1878),[15] Kozłowski (1895)[16] and Gutwiński (1897).[17] Mrozińska[3][4][5] was the first to examine the genus in terms of morphology, ecology and distribution and described more than 400 species, mainly from southern Poland.
In 1900, Hirn wrote a monograph concerning his finding of a new taxon, to which he gave the name Oedogoniaceen. This paper was published and translated 60 years later. Hirn discovered Oedogonium in a ditch, appearing from June – October.[18]