A new water mold in the Blastocladiales has been isolated and cultivated and is now described. It is placed in the genus Blastocladiopsis along with the previously known B. parva. The most striking feature of the new organism is the prominent reticulate ornamentation of the resistant sporangia. This same feature was illustrated in a partial description of a water mold isolated in 1936 by Sörgel, and it is thought that Sörgel's species might be the same as the one described here. Zoospores from both zoosporangia and resistant sporangia give rise to the same type of thallus; therefore, the organism appears to lack sexuality.