The first monograph of fungi the family Endogonaceae Paol. was prepared by Thaxter (1922). This family was located in the order Mucorales of the class Zygomycetes and consisted of four genera: Endogone Link: Fries, Glaziella Berk., Sclerocystis Berk. & Broom, and Sphaerocreas Sacc. & Ellis. The monotypic genus Sphaerocreas was later transferred to the genus Endogone (Zycha 1935). The fungi existing in the family Endogonaceae produced both azygospores and chlamydospores. Thaxter (1922) considered chlamydosporic species to be anamorphs of azygosporic fungi.
In the revision of the Endogonaceae prepared by Gerdemann and Trappe (1974), members of this family were further included in the order Mucorales. The Endogonaceae contained seven genera: Acaulospora Gerd. & Trappe gen. nov., Endogone, Gigaspora Gerd. & Trappe gen. nov., Glaziella Berk., Modicella Kanouse, and Sclerocystis Berk. & Broome. The fungi were recognized or considered to be saprotrophs and to form ecto- or arbuscular mycorrhizae.
In the reduced order Mucorales, Benjamin (1974) remained fungi that mainly were saprotrophs or nonhaustorial parasites and reproduced asexually by sporangia, sporangiola, merosporangia, and sometimes by chlamydospores, arthrospores, and yeast-like cells. Consequently, he transferred the family Endogonaceae to the order Endogonales Moreau ex R.K. Benjamin erected by Moreau (1953).
In 1984, Trappe and Schenck transferred the genus Modicella to the Mortierellaceae (Zygomycota), and the presence of septa in fragments of sporocarps of Glaziella aurantiaca (Berk. & Curtis) Cooke was the base to erect a new order, Glaziellales J.L. Gibson (=Pezizales J. Schtöt) with one family, Glaziellaceae J.L. Gibson (Ascomycota; Gibson et al. 1986).
In 1990, Morton and Benny segregated from the family Endogonaceae Paol. emend. J.B. Morton & Benny soil-borne fungi forming arbuscules in roots of terrestrial plants and located them in a new order, Glomales J.B. Morton & Benny. Fungi of the genus Endogone remained in the family Endogonaceae of the order Endogonales Moreau ex R.K. Benjamin emend. J.B. Morton & Benny with taxa producing only zygospores. Now, arbuscular fungi exist in the phylum Glomeromycota C. Walker & Schuessler (Schüßler et al. 2001).
At present, the order Endogonales in the class Zygomycetes of the phylum Zygomycota includes one family, the Endogonaceae. This family consists of four genera, i. e., Endogone Link: Fr., Peridospora C.G. Wu & Such J. Lin, Sclerogone Warcup, and Youngiomyces Y.J. Yao.
By definition, fungi of the genus Endogone form hypogeous or epigeous sporocarps with zygosporangia developing from the tip of one of two united gametangia (Gerdemann and Trappe 1974; Pegler et al. 1993). The zygosporangia are or are not enveloped in a hyphal mantle. Two species, E. flammicorona Trappe & Gerd. and E. lactiflua Berk. & Broom, were found to form ectomycorrhizae (Fasssi 1965; Gerdemann and Trappe 1974; Walker 1985).
The genus Peridiospora was proposed to include hypogeous fungi developing similarly as those of Endogone spp., but producing mantled zygosporangia singly in the soil (Wu and Lin 1997). Currently, two species of Peridiospora are known.
The one-species genus Sclerogone was established from hypogeous, minute, <0.5 mm, brown sporocarps containing 2-12(-78), hyaline zygosporangia (Warcup 1990). Sclerogone eucalypti Warcup produced ectomycorrhizae in eucalypts.
The reason of the transfer of three Endogone spp. to and the description of one new species in a new order, Youngiomyces, was the presence of two or three gametangia in separated places of epigeous zygosporangia (Yao et al. 1995).
The existence of the genus Peridiospora seems to be doubtful, because the author of this website found single zygosporangia of species also forming zygosporangia in both compact sporocarps (E. lactiflua Berk. & Broom, E. flammicorona Trappe & Gerd.) and loose aggregates (E. aurantiaca Blaszk., E. maritima Blaszk. et al.; Blaszkowski 1997; Blaszkowski et al. 1998).
The method commonly used in collecting of fungi of the genus Endogone is raking and searching through the leaf litter and the upper layer of soil (Gerdemann and Trappe 1974; Pegler et al. 1993). In contrast, the zygosporangia used to establish the genus Peridiospora were wet-sieved from the soil, similarly as those of the Endogone spp. mentioned above.
In studies of the author of this website, the sieve with meshes of a diameter of 250 µm used collected large sporocarps and larger aggregates of Endogone spp., whereas that with openings of a diameter of 40 µm retained small aggregates and single spores of the same fungi. Blaszkowski et al. (1998) suggested that the formation of sporocarps culminates the ontogenetical development of this group of fungi and the size of sporocarps may depend on the stability, as well as physical and chemical properties of the soil, in which a given fungus origins.
At present, the family Endogonaceae contains 22 species listed below.
Endogone Link ex Fries
Endogone acrogena Gerd., Trappe & Hosford
Endogone alba (Petch) Gerd. & Trappe
Endogone aurantiaca Blaszk.
Endogone crassa P.A. Tandy
Endogone flammicorona Trappe & Gerd.
Endogone incrasata Thaxt.
Endogone lactiflua Berk. & Broom
Endogone maritima Blaszk., Tadych & Madej
Endogone oregonensis Gerd. & Trappe
Endogone pegleri Y.J. Yao
Endogone pisiformis Link ex Fries
Endogone pseudopisiformis Y.J. Yao
Endogone reticulata P.A. Tandy
Endogone tuerculosa Lloyd
Endogone verrucosa Gerd. & Trappe
Sclerogone Warcup
Type species: Sclerogone eucalypti Warcup
Youngiomyces Y.J. Yao
Type species: Youngiomyces carolinensis Y.J. Yao
Youngiomyces carolinensis
Y.J. Yao
Youngiomyces aggregatus Y.J. Yao (=Endogone aggregata P.A.
Tandy)
Youngiomyces multiplex (Thaxt.) Y.J. Yao (=Endogone multiplex
Thaxter)
Youngiomyces stratosus (Trappe, Gerd. & Fogel) Y.J. Yao (=Endogone
stratosa Trappe, Gerd. & Fogel)
Peridospora C.G. Wu & Suh J. Lin
Type species: Peridospora tatachia C.G. Wu & Suh J. Lin
Peridospora tatachia
C.G. Wu & Suh J. Lin
Peridospora reticulata C.G. Wu & Suh J. Lin
To date, the author of this website found four species of the genus Endogone. All were revealed in rhizosphere soil samples coming from Poland. The specimens of E. flammicorona collected are in a poor condition and therefore this fungus was not include in the list presented below.
REFERENCES
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Blaszkowski J. 1997. Endogone aurantiaca, a new species in the Endogonales from Poland. Mycotaxon 63, 131-141.
Blaszkowski J., Tadych M., Madej T. 1998. Endogone maritima, a new species in the Endogonales from Poland. Mycol. Res. 102, 1096-1100.
Fassi B. 1965. Micorrhize ectotrofiche di Pinus strobus L. prodotte da un’Endogone (Endogone lactiflua Berk.). Allionia 11, 7-15.
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Trappe J. M., Schenck N. C. 1982. Taxonomy of the fungi forming endomycorrhizae. In: Schenck N. C. (ed.). Methods and principles of mycorrhizal research. Amer. Phytopath. Soc. St. Paul., MN, 1-9.
Walker C. 1985. Endogone lactiflua forming ectomycorrhizas with Pinus contorta. Trans. Br. Mycol. Soc. 84, 353-355.
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Wu C-G., Lin S-J. 1997. Endogonales in Taiwan: a new genus with unizygosporic sporocarps and a hyphal mantle. Mycotaxon 64, 179-188.
Yao Y-J., Pegler D. N., Young T. W. K. 1995. Youngiomyces, a new genus in Endogonales (Zygomycotina). Kew Bull. 50, 349-357.
Zycha H. 1935. Mucorineae. Kryptogamenfl. Mark Brandenburg 6a, Leipzig, 264 pp.