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Diatoms of the United States is now known as Diatoms of North America.
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External tube



A hyaline area of thickened silica extending from the central area of some pennate diatoms. A transverse fascia is formed by secondary deposition of silica into depressions on the valve. Examples of genera having a transverse fascia include Luticola and Staurophora. Plural form is fasciae.

See also stauros for a similar structure.


Cox, E.J. (2012). Ontogeny, homology, and terminology - wall morphogenesis as an aid to character recognition and character state definition for pennate diatom systematics. Journal of Phycology 48: 1–31. 10.1111/j.1529-8817.2011.01081.x