Agardh 1824      Category: Centric
TYPE SPECIES: Melosira nummuloides Agardh




Smallest to largest - 4 taxa sorted by maximum length

Image Credit: Marina Potapova, Sarah Spaulding

CLASS: Coscinodiscophyceae
  ORDER: Thalassiosirales
    FAMILY: Melosiraceae

  1. Valve wall uniform in structure, little external ornamentation
  2. Frustules lack costae, septae, and spines
  3. Frustules may form colonies

Melosira valves have little ornamentation. They lack distinctive features including costae, septae, and spines. Frustules form long colonies linked at the valve face.

Melosira contains a small number of freshwater species. M. varians, one of the most common species of the genus grows in benthic habitats of eutrophic streams and lakes. Melosira also contains the species M. undulata, which grows in large, oliogotrophic lakes of western North America as well as dystrophic rivers.

Cite This Page:
Spaulding, S., and Edlund, M. (2008). Melosira. In Diatoms of the United States. Retrieved April 24, 2018, from

Contributor: Sarah Spaulding | Mark Edlund - December 2008
Reviewer: Sam Rushforth - June 2010