The extinct genus Hedstroemia was once thought to be a rivulariacean cyanobacterium.

It forms oval blobs composed of sinuous tubes that have rounded outlines and occurs in conjunction with Solenopora.

[3] Hedstroemia was formerly assigned to the now obsolete taxon porostromata.

[4] In 2020, the genus was assigned to the cyanobacteria order Nostocales.

This Ulvophyceae-related article is a stub.