Chytrid Fungi Online
An NSF PEET project website

Here you will find information on members of the Phylum Chytridiomycota, including a description of genera, tips and techniques on how to isolate chytrids, current hypotheses of chytrid systematics (includes both taxonomy and phylogeny), links to other relevant websites, and a searchable reference database. The goal of this site is to provide an online resource for students, teachers, and researchers wanting to learn more about chytrids as well as an easily accessed interface for taxonomic information. For powerpoint presentations designed for the teaching classroom and laboratory, click here. Since the work on chytrid taxonomy and phylogeny is an on-going process, this site will be continually updated to reflect the changes brought about by new research.


The Phylum Chytridiomycota (chytrids) includes two classes, Chytridiomycetes and Monoblepharidomycetes (2), each of which is monophyletic based on molecular analyses (3). Because of their genetic and morphological divergence, two groups of zoosporic fungi once included among chytrids are now classified as separate Phyla, Blastocladiomycota and Neocallimastigomycota (1, 2). To see a phylogeny of zoosporic fungi based on analyses of ribosomal gene sequences (3-8) click here.


The Chytridiomycetes are currently separated into nine orders [Chytridiales (3,4,9), Rhizophydiales (5), Spizellomycetales (1), Rhizophlyctidales (6), Cladochytriales (7), Lobulomycetales (8), Polychytriales (10), Gromochytriales (11) and Mesochytriales (11)]. Molecular phylogenetic analyses (3-8) have demonstrated that each order is monophyletic with the current circumscription of the Chytridiales (9). Work is progressing on characterization of clades for groups formerly included in the Chytridiales. James et al. 2006 (3) molecular analyses place two genera assigned to the Spizellomycetales outside of the core chytrid clade. The genus Rozella appears basal to the core chytrids and Olpidium brassicae is within the radiation of zygomycetes. Thus, their classification is uncertain at this time (incertae sedis). To learn more about the orders of chytrids, click on one of the thumbnail pictures below.


Monograph and interactive key to species of Chytriomyces



Check out our monograph and interactive keys to Rhizophydium species
Tabular comparisons of Rhizophydium species .


Monograph and interactive key to species of Karlingiomyces




RECENTLY ESTABLISHED Order = Gromochytriales (11)

RECENTLY ESTABLISHED Order = Mesochytriales (11)



See "Monoblepharidales in the Classroom" by Marilyn R.N. Mollicone



(1) Barr, D. J. S. 1980. An outline for the reclassification of the Chytridiales, and for a new order, the Spizellomycetales. Canadian Journal of Botany 58, 2380–2394.

(2) Hibbett, D.S., M. Binder, J. Bischoff, M. Blackwell, P. Cannon. O. Eriksson, S. Huhndorf, T. James, P. Kirk, R. Lucking, T. Lumbsch, F. Lutzoni, P. Matheny, D. McLaughlin, M. Powell, S. Redhead, C. Schoch, J. Spatafora, J. Stalpers, R. Vilgalys, et al. 2007. A higher level phylogenetic classification of the fungi. Mycological Research 111: 509-547.

(3) James, T.Y., P.M. Letcher, J.E. Longcore, S.E. Mozley-Standridge, D. Porter, M.J. Powell, G.W. Griffith, and R. Vilgalys. 2006. A molecular phylogeny of the flagellated Fungi (Chytridiomycota) and description of a new phylum (Blastocladiomycota). Mycologia 98: 860-871.

(4) Letcher, P. M., M. J. Powell, J. G. Chambers, J.E. Longcore, J. E., P.F. Churchill, and P. M. Harris. Ultrastructural and molecular analysis of the Chytridiaceae (Chytridiales). Canadian Journal of Botany 83, 1561-1573 (2005).

(5) Letcher, P.M., M.J. Powell, P.E. Churchill, and J.G. Chambers. 2006. Ultrastructural and molecular phylogenetic delineation of a new order, the Rhizophydiales (Chytridiomycota). Mycological Research 110: 898-915.

(6) Letcher, P.M., M. J. Powell, Donald J. S. Barr, Perry F. Churchill, William S. Wakefield, and Kathryn T. Picard. 2008. Rhizophlyctidales is a new order in Chytridiomycota. Mycological Research 112: 1031-1048.

(7) Mozley-Standridge, S.E., P.M. Letcher, J.E. Longcore, D. Porter, and D. R. Simmons. 2009. Cladochytriales - a new order in Chytridiomycota. Mycological Research 113: 498-507.

(8) Simmons, D.R., T.Y. James, A.F. Meyer, and J. E. Longcore. 2009. Lobulomycetales, a new order in the Chytridiomycota. Mycological Research 113: 450-460.

(9) Vélez, C.G., P.M. Letcher, S. Schultz, M.J. Powell, and P.F. Churchill. 2011.Molecular phylogenetic and zoospore ultrastructural analyses of Chytridium olla establish the limits of a monophyletic Chytridiales. Mycologia 103: 118-130.

(10) Longcore J.E., and D.R. Simmons. 2012. The Polychytriales ord. nov. contains chitinophilic members of the rhizophlyctoid alliance. Mycologia 104: 276-194. DOI: 10.3852/11-193

(11) Karpov S.A., A A. Kobserva, M.A. Mamkaeva, K.A. Mamkaeva, K.V. Mikhailov, G.S. Mirzaeva, V.V. Aleoshin. 2014. Gromochytrium mamkaevae gen. & sp. nov. and two new orders: Gromochytriales and Mesochytriales (Chytridiomycetes). Persoonia 32: 115-126.


Funding for this site was provided by the National Science Foundation's PEET Program (Partnerships for Enhancing Expertise in Taxonomy) and REVSYS Program (Revisionary Systematics):

  • (DEB-9978094; 9/1/99 to 9/31/2005): "Monographic Research on the Zoosporic Fungi, Chytridiomycetes"
  • (DEB-0529694; 9/1/05 to 8/31/2011): "Phylogenetic and Monographic Research on Spizellomycetalean Chytrids (Chytridiomycota)"

  • (DEB - 9/1/05 to 8/31/2009): "Phylogenetics and Taxonomic Revision of the Rhizophydium Clade."
  • Disclaimer:
    Research cited on this website was supported by the National Science Foundation's programs on Partnerships for Enhancing Expertise in Taxonomy (PEET) and REVSYS. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation or the institutions supporting the authors.

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