Fragilaria
Lyngbye 1819 Category: Araphid
TYPE SPECIES: Fragiliaria pectinalis (O. Müller) Lyngbye
Image Credit: Eduardo Morales
CLASS: Fragilariophyceae
ORDER: Fragilariales
FAMILY: Fragilariaceae
- Frustules rectangular to lanceolate, in girdle view
- Frustules joined by spines to form colonies
- Single rimoportula present
Fragilaria frustules are rectangular to lanceolate in girdle view. The pattern of ornamentation on the valve face is variable, but a central sternum is generally present. Frustules are joined by small marginal spines to form ribbon like (band-shaped) colonies. A single rimoportula is present, usually positioned at a distal end. Small, apical porefields are also present. Living cells contain plastids composed of 2 plates, positioned against the valve face.
Fragilaria is often abundant in the plankton of lakes, including the species F. crotonensis, F. capucina, and F. vaucheria. Like Asterionella formosa, F. crotonensis is a species that is considered to have a world wide distribution and is also considered to be introduced by human activities.
A broad concept of Fragilaria is applied in Krammer and Lange-Bertalot (1991), while a much narrower concept is applied in Williams and Round (1987). Depending upon the school that a particular author follows, species may be considered within Fragilaria, Synedra, or a number of other genera. This website generally follows the work of Williams and Round (1987).
Cite This Page:
Spaulding, S., and Edlund, M. (2009). Fragilaria. In Diatoms of the United States. Retrieved May 22, 2013, from http://westerndiatoms.colorado.edu/taxa/genus/Fragilaria
Contributor: Sarah Spaulding | Mark Edlund - January 2009
Reviewer: Sam Rushforth
Citations
Hustedt, F. (1930). Die Kieselalgen Deutschlands, Osterreichs und der Schweiz mit Berucksichtigung der ubrigen Lander Europas sowie der angrenzenden Meersgebiete. In: Dr. L. Rabenhorst's Kryptogamen-Flora von Deutschland, Osterreich und der Schweiz. Leipzig, Akademische Verlagsgesellschaft Geest und Portig K.-G. Vol. 7, Part 3, pp. 557-816.
Krammer, K. and Lange-Bertalot, H. (1991). Bacillariophyceae. 3. Teil: Centrales, Fragilariaceae, Eunotiaceae. . In Ettl, H., Gerloff, J., Heynig, H. & Mollenhauer, D. (Eds.). Süsswasserflora von Mitteleuropa. 2(3): 1-576. Gustav Fisher Verlag, Stuttgart, Germany.
Patrick, R.M. and Reimer, C.W. (1966). The Diatoms of the United States exclusive of Alaska and Hawaii, V. 1. Monographs of the Academy of Natural Sciences of Philadelphia 13.