Fungalpedia – Note 3329, Blastocladiomycetes
Blastocladiomycetes Doweld, Prosyllabus Tracheophytorum, Tentamen Systematis Plantarum Vascularium (Tracheophyta) (Moscow): LXXVII (2001).
Citation when using this data: Wijayawardene NN et al. 2024 – Fungalpedia.
Index Fungorum, Faceoffungi, MycoBank, GenBank, Fig 1.
Classification: Blastocladiomycotina, Blastocladiomycota, Blastocladiomyceta, Fungi.
Thallus monocentric, polycentric or filamentous (sometimes presenting pseudosepta); zoospore with a single posteriorly oriented whiplash flagellum that lacks electron-opaque shield present in the kinetosome transition region, characterized by the presence of lateral membrane cisterna known as side-body complex (SBC), membrane-bound ribosomal aggregation known as a ribosomal cap (nuclear cap) containing a single cone-shaped nucleus that terminates adjacent to the kinetosome, cytoplasmic microtubules with anteriorly radiating roots leading from the proximal portion of the kinetosome continuing on to wrap around a nucleus; resting sporangium darkly pigmented and usually ornamented with spines or other projections. Asexual reproduction through posteriorly uniflagellate chemotactic zoospores (flagellated asexual spores), sexual reproduction through planogamete fusion with a sporic meiosis type of life cycle involving alternation of a haploid gametophytic (which produces gametes) with a diploid sporophytic (produces asexual spores) generation (James et al. 2006b).
Life mode and distribution: The members of Blastocladiomycetes are widely distributed in a broad range of aquatic and terrestrial ecosystems throughout the world and are reported commonly as saprotrophs, feeding on decomposing organic matter, with different types of life cycle. This very large and morphologically diverse class also contains many parasites of various soil inhabiting small invertebrates, their eggs and fungi in water-logged soil or water (Sparrow 1960; Karling 1977; James et al. 2014; Powell 2017).
Notes: Doweld (2001) introduced this class to accommodate Blastocladia Reinsch 1877 (Blastocladiaceae, Blastocladiales). James et al. (2006b) also introduced Blastocladiomycetes but it is an isonym of Blastocladiomycetes Doweld. Currently, the class comprises three orders i.e. 1. Blastocladiales (families Blastocladiaceae H.E. Petersen, Catenariaceae Couch, Paraphysodermataceae Doweld, and Sorochytriaceae Dewel); 2. Callimastigales Doweld (families: Callimastigaceae Fonseca); 3. Catenomycetales Doweld (Catenomycetaceae Doweld, Coelomomycetaceae Couch).
Type order: Blastocladiales H.E. Petersen [as ‘Blastocladiineae’], Bot. Tidsskr. 29: 357 (1909).
Type family: Blastocladiaceae H.E. Petersen, Bot. Tidsskr. 29: 357 (1909).
Type genus: Blastocladia Reinsch, Jb. wiss. Bot. 11(2): 291 (1877).
Type species: Blastocladia pringsheimii Reinsch [as ‘pringsheimi’], Jb. wiss. Bot. 11(2): 367 (1877).
Other accepted species: Species Fungorum – search Blastocladiomycetes.
Figure 1 – Microscopic characteristics of Allomyces spp. (Blastocladiaceae, Blastocladiales, Blastocladiomycetes). a Mature thallus of Allomyces neomoniliformis with some empty zoosporangia and resistant sporangia. b Young developing thallus of Allomyces moniliformis. c Dark brown and thick-walled resistant sporangia of Allomyces neomoniliformis. d-f Hypha with thin-walled zoosporangia in Allomyces moniliformis. g-i Thin-walled zoosporangia with papillae of Allomyces moniliformis. Scale bars: a = 60 µm, b = 100 µm, c = 40 µm, d-f = 100 µm, g-i = 50 µm.
References
Karling JS. 1977 – Chytridiomycetarum Iconographia. Monticello, New York: Lubrecht Cramer.
Entry by
Nalin N. Wijayawardene, Center for Yunnan Plateau Biological Resources Protection and Utilization, College of Biological Resource and Food Engineering, Qujing Normal University, Qujing, Yunnan 655011, P.R. China, Tropical Microbiology Research Foundation, 96/N/10, Meemanagoda Road, 10230 Pannipitiya, Sri Lanka, Department of Bioprocess Technology, Faculty of Technology, Rajarata University, Sri Lanka
Published online 2 October 2026