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Invasive Species: Starry Stonewort

Starry Stonewort

(Nitellopsis obtusa)
*Established in Michigan*


Report this species:

Use the Midwest Invasive Species Information Network (MISIN) online reporting tool

- Or - download the MISIN smartphone app and report from your phone -



  • Whorls of 4-6 branchlets/leaves with blunt tips.
  • Star-shaped bulbils are produced at the nodes, generally 3-6 mm wide.
  • Can reach up to 33 inches in length.

starry stonewort
Photo courtesy of Paul Skawinski.

starry stonewort mass
Photo courtesy of Scott Brown.

starry stonewart
Starry stonewort bulbil. Photo courtesy of Paul Skawinski.

Habitat: This submerged annual macroalga invades lakes, ponds, reservoirs and slow moving rivers. It will inhabit freshwater habitats ranging from 3 feet to 95 feet in depth.

Native Range: Europe and western Asia.

U.S. Distribution: Michigan, northern Indiana, southeastern Wisconsin, Minnesota, and the northeast United States

Local Concern: Starry stonewort forms dense mats in lakes and can significantly reduce the diversity of other aquatic plants. Dense mats of vegetation can also impede movement of fish, spawning activity, water flow and recreational activities.

Native look-alikes and how you can tell them apart from starry stonewort:

  • Chara: Feels scaly and brittle, often smells like a skunk’s spray.


Starry Stonewort Invasive Species Alert - Printable PDF

Status and Strategy for Starry Stonewort Management This document provides in-depth information about starry stonewort in Michigan including identification, distribution, management and control options.

MDARD Weed Risk Assessment for Starry Stonewort (Nitellopsis obtusa) - This document evaluates the invasive potential of the plant species using information based on establishment, spread and potential to cause harm.