Fragilariforma
Williams and Round 1988 Category: Araphid
TYPE SPECIES: Fragilariforma virescens (Ralfs) Williams and Round
Image Credit: Eduardo Morales, Kerry Howard, Loren Bahls, Sarah Spaulding
CLASS: Fragilariophyceae
ORDER: Fragilariales
FAMILY: Fragilariaceae
- Central sternum very narrow, or absent
- Cells joined by spines to form colonies
- Striae uniseriate
The valve margins of Fragilariforma are variable and may be linear, lanceolate, or elliptical with rostrate to capitate apices. In girdle view, frustules are rectangular in shape. Fragilariforma valves are characterized by a very narrow, or absent, central sternum. Striae are composed of distinct, uniseriate areolae. Frustules form linear colonies, linked by small marginal spines into ribbon like (band-shaped) colonies. A single rimoportula is present at one pole and is aligned with a stria. Living cells contain multiple discoid plastids.
Some species of Fragilariforma grow in ephemeral habitats, subject to periodic drying. In such habitats, frustules often form internal valves. Several species are typical of boreal wetlands and others are endemic to subtropical regions.
Cite This Page:
Spaulding, S., and Edlund, M. (2009). Fragilariforma. In Diatoms of the United States. Retrieved May 23, 2013, from http://westerndiatoms.colorado.edu/taxa/genus/Fragilariforma
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.
Kilroy, C., Sabbe, K., Bergey, E.A., Vyerman, W. and Lowe, R. (2003). New species of Fragilariforma (Bacillariophyceae) from New Zealand and Australia. New Zealand Journal of Botany 41: 535-554.
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.
Tuji, A. and Williams, D.M. (2008). Examination of type material of Fragilaria mesolepta Rabenhorst and two similar, but distinct, taxa. Diatom Research, 23(2): 503-510.
Williams, D.M. and Round, F.E. (1988). Fragilariforma, nom. nov., a new generic name for Neofragilaria Williams & Round. Diatom Research 3: 265-267.