The Spizellomycetales mostly occur in soil and are seldom found in strictly aquatic habitats. Both saprophytic and parasitic forms are present within the group. All members of the order are monocentric and, when rhizoids are present, their tips are usually blunt (diameters greater than 0.5 µm). Sexual reproduction is unknown.
This order was created by Barr (1980) to recognize the difference of its zoospores from those of the Chytridiales, especially with respect to their ultrastructure. Zoospores of this order have a nucleus that is usually spatially associated with or connected to the kinetosome. The non-flagellated centriole usually does not lie parallel to the kinetosome and the two are usually connected at the ends closest to the nucleus. Zoospores of this order lack rumposomes and the microtubule rootlets, when present, do not arise from the side of the kinetosome; they arise from a microtubule organizing center (MTOC) near the kinetosome. Zoospore ribosomes are generally dispersed and there are usually several lipid globlules in the spores.
Complete list of Genera:
- Caulochytrium
- Gaertneriomyces
- Kochiomyces
- Olpidium
- Rozella
- Spizellomyces
- Triparticular
- Urophlyctis
References, Keys and Illustrated Descriptions:
Barr, D.J.S. 1980. An outline for the reclassification of the Chytridiales, and for a new order, The Spizellomycetales. Can. J. Bot. 58: 2380-2394.
Barr, D.J.S. 1984. The classification of Spizellomyces, Gaetneriomyces, Triparticalcar and Kochiomyces (Spizellomycetales, Chytridiomycetes). Can. J. Bot. 62: 1171-1201.
Karling, J.S. 1977. Chytridiomycetarum Iconographia. Lubrecht and Cramer, Monticello, New York.
Sparrow, F.K. 1960. The aquatic Phycomycetes, 2nd ed. Rev. Univ Michigan Press, Ann Arbor.