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Diatoms of the United States is now known as Diatoms of North America.
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Patrick in Patrick & Reimer 1966      Category: Araphid
TYPE SPECIES: Hannaea arcus (Ehrenberg) Patrick in Patrick & Reimer




Smallest to largest - 2 taxa sorted by maximum length

Image Credit: Becky Bixby, Megan Otu

CLASS: Fragilariophyceae
  ORDER: Fragilariales
    FAMILY: Fragilariaceae

  1. Valves arched
  2. Poles capitate to rostrate
  3. Valve with central ventral swelling
  4. Faint (ghost) striae near central swelling

Valves are linear and arched. One or two rimoportulae occur on each valve, located near the valve ends. The ventral (concave) side of the valve has a central swelling. Faint, or ghost striae, are often present near the center of the valve.

Hannaea is characteristic of oligotrophic streams and large lakes, where it grows attached in tufted colonies to benthic surfaces.

Cite This Page:
Spaulding, S., and Edlund, M. (2008). Hannaea. In Diatoms of the United States. Retrieved May 27, 2018, from

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