Large alga
Starry Stonewort
Nitellopsis obtusa
These illustrations are AI-generated, not photographs, and are not to scale. They show what to look for; they are not a substitute for an expert identification.
How to identify it
Size: Strands can be several feet long. The star-shaped bulbils are only a few millimeters across.
- Not a true plant but a large green alga with a stem-like body.
- Rings (whorls) of long, smooth, bright-green branchlets of different lengths.
- Long gaps between the rings.
- Tiny pale, star-shaped bulbils on the root-like strands near the base. These are the giveaway: gently pull up a clump to look.
Don’t confuse it with
Native Chara, also called muskgrass, feels rough or gritty and often smells musky. Native Nitella has branchlets that fork evenly at the tips and no star-shaped bulbils.
Where it came from
Native to Europe and western Asia.
First found in North America in the St. Lawrence River in the late 1970s, likely carried in ships' ballast water. Pieces and bulbils reach inland lakes on boats, trailers and gear.
Earliest dated Indiana record: 2008, Lake Wawasee near Syracuse, Kosciusko County. This is the oldest dated record in the USGS non-native species database, not necessarily when it first arrived.
Why it matters
It can grow into thick mats several feet deep that crowd out native plants, cover the areas where fish spawn and make boating and swimming difficult.
Indiana law
Listed in Indiana's Aquatic Plant Rule (312 IAC 18-3-23), which makes it illegal to sell, give away, barter, exchange, distribute, transport or introduce the plant in Indiana. Fines can apply for carrying listed plants on vehicles, boats or trailers. Indiana DNR’s page.
If you find it
- Don’t move it. Before leaving the water, remove all plants, mud and debris and drain all water from your boat, motor, live well, bilge and trailer. Carrying plants listed in Indiana’s Aquatic Plant Rule on vehicles, boats or trailers is illegal and can bring fines. Clean boater tips
- Never release bait or pets. Don’t dump bait, aquarium animals or water-garden plants into any lake or stream. Put unused bait in the trash.
- Report it. Take a photo, note where you saw it, and report it through EDDMapS or the GLEDN phone app, or contact Indiana DNR’s aquatic invasive species program at 317-234-3883 or ais@dnr.IN.gov. Experts there can confirm what you found.
- Ask before removing or treating. On public lakes, any control of aquatic plants — chemical, mechanical, physical or biological — needs an Indiana DNR aquatic vegetation control permit. When a permit is needed
Indiana lakes where it has been recorded
3 Indiana lakes on this site have a record of this species.
A lake that is not listed may still have it. Records exist only where someone found the species and reported it, so “not recorded” does not mean “not present.”
Lake records: Midwest Glacial Lakes Partnership Conservation Planner; underlying records from the USGS Nonindigenous Aquatic Species database.
Sources
- Indiana Clean Water Corps: Starry stonewort fact sheet
- Indiana DNR: Aquatic invasive species, plants
- Indiana Aquatic Plant Rule, 312 IAC 18-3-23: what you need to know
Earliest dated record: USGS Nonindigenous Aquatic Species database.