[5] Spiny hornwort can be found in ponds and lakes, principally in eastern North America.

The specific epithet echinatum comes from echinus which means sea urchin or hedgehog.

It does not typically have any roots with stems that are freely branching and up to 4 m (13 ft) in length.

The fruits have dry seeds with spines and a rough surface.

[9] Several states list this species as special concern (Maine, Tennessee), threatened (New York), or endangered (Maryland, New Jersey).