Scientific name: Nitellopsis obtusa

What Is It?

Starry stonewort is an aquatic, grass-like algae that spreads rapidly and alters water chemistry. It may be found in both freshwater and estuarine environments.

Is It Here Yet?

No. However, it is a very harmful invasive species elsewhere in the United States, such as Michigan, and has the potential to spread on boats that are not cleaned properly before traveling between water bodies. Evidence indicated it is also spread by waterfowl.

Why Should I Care?

Starry stonework grows densely, covering the sediment and forming mounds of vegetation up to 6 feet tall. It can outcompete other aquatic plants, harming habitat for fish and other wildlife by reducing cover and food sources. It also impacts ecosystems by absorbing phosphorous and changing the chemistry of sediment. When it becomes established it can smother fish spawning grounds and reduce habitat diversity. Its dense mats of vegetation also inhibit boating, swimming, and other recreational uses of water bodies.

How Can We Stop It?

Do not purchase, plant, or trade this species. Dump aquarium contents appropriately. Be sure to check boats, trailers, and motors before launching a boat into a waterway to ensure there are no plant fragments that may spread to waterways.

What Are Its Characteristics?

  • The distinguishing characteristic is the six-pointed star-shaped white ‘bulbil’ (a small bulb-like structure) at the nodes of its stems. These are especially common at the base of the plants, and can be found during all times of the year
  • It can grow up to 33 inches long, but grows in dense tangled mounds when established
  • Its blunt-tipped branchlets grow in whorls of four to six. The branchlets are uneven in length, unlike the native plant-like algae

Additional Photographs