About Nitellopsis obtusa (Desv.) J.Groves
Nitellopsis obtusa (Desv.) J.Groves has long, fairly straight branches arranged in whorls. These branches attach to the stem at nodes at an acute angle. Both the stem and branches are approximately 1 millimeter (0.04 inches) in diameter. The internodal sections of the stem are each made up of a single cell that can reach several centimeters in length. Stems can grow up to 80 centimeters (31 inches) long, or even longer, and form dense masses. When actively growing, this alga is light green in color. Creamy-white bulbils may grow at the base of the main stems, and its rhizoids are star-shaped. Individual plants are either male or female. Female reproductive structures called oogonia develop at the base of upper branchlets, and can produce orange to red oocytes. This feature distinguishes the species from the similar musk-grass and brittlewort. This alga grows in freshwater at depths greater than 4 meters (13 feet), on soft substrates including silt, sand, and accumulated detritus. It typically grows in deep, slow-moving water where few other plants grow, most often near docks and marinas. Nitellopsis obtusa is widely distributed across Europe and Asia. In the British Isles, it has only been recorded at a small number of sites, including Cosmeston Lake in the Vale of Glamorgan. It has invaded the Laurentian Great Lakes in North America.
