SPECIES DESCRIPTIONS AND ILLUSTRATIONS

Below are links to pages showing diagnostic descriptions and illustrations of the species of fungi characterized in this website. Additionally, the content of each page shows (1) disease symptoms when the fungus treated is a pathogen; (2) the plant host of the fungus characterized or the substrate utilized by it; (3) its distribution in both Poland and the other regions of the world; (4) the name of the anamorphic or teleomorphic state of the fungus (if known); (5) comments on the life-cycle of the fungus discussed and favourable conditions for its development and dissemination; when the fungus presented is pathogenic, its economic importance is also showed; and (6) the literature cited.

ASCOMYCOTA

Diaporthales

Members of the order Diaporthales form perithecial ascospores in a stroma of fungal and substrate tissues or directly from somatic hyphae on the substrate. Asci are persistent, clavate or cylindrical, thick-walled, and have conspicuous J- refractive apical ring. Ascospores are hyaline to brown and one- to many-septate. Anamorphs of this order are many coelomycetous species. The Diaporthales comprises two families, 94 genera, and 447 species. Among them, many important plant pathogens and saprobes occur. The most important genera of this order are, e.g., Diaporthe, Gnomonia, and Gaeumannomyces (Alexopoulos et al. 1996; Kirk et al. 2001).

Dothideales

The order Dothideales comprises species forming dark brown perithecial ascomata as lysigenous locules within stromatic tissue. Asci are ovoid to cylindrical, thick-walled, fissitunicate, have clearly defined ocular chamber but have no other apical structures. Ascospores are hyaline to brown, one- to many-celled or sometimes muriform. When known, anamorphs are coelomycetous. The Dothideales consists of five families, 190 genera, and 533 species being saprobes or necrotrophic parasites of different plant species. The most important members of Dothideales are species of the genera Ampelomyces, Botryosphaeria, and Dothidea (Kirk et al. 2001).

Erysiphales

The order Erysiphales includes fungi forming globose, dark-coloured cleistothecial ascomata, usually with complex appendages. Asci are solitary to few, broadly clavate, thin-walled, with two layers at the base and one layer at the apex. Ascospores are hyaline to yellowish, subglobose to ellipsoidal-ovoid, aseptate. Anamorphs are hyphomycetous, of the genera, e.g., Oidium, Oidiopsis, and Ovulariopsis.

The fungi of the order Erysiphales are obligate biotrophs and cause an especially harmful group of plant diseases known as powdery mildews. The name comes from a white, powdery coating covering infected plant parts, mainly leaves and stems. The white coating is formed by dense aggregations of conidiophores and conidia called "oidia" of the anamorphic states of fungi of this order.

The order Erysiphales consists of one family, 13 genera, and 494 species. Based on molecular examinations, Braun and Takamatsu (2000) introduced a new generic taxonomy (classification) of powdery mildew fungi. Species of all genera with pseudoidium anamorphs. i. e., Erysiphe s. str., Microsphaera, Uncinula, and Uncinuliella, were united in Erysiphe emend.

Among the most serious pathogens are members of the genera Blumeria, Erysiphe, Microsphaera, Phyllactinia, Podosphaera, Sphaerotheca, and Uncinula (Agrios 1988; Alexopoulos et al. 1996).

Helotiales

The order Helotiales is represented by fungi forming usually small, frequently brightly coloured, sessile or stipitate, cupulate or discoid, rarely convex, sometimes surrounded by conspicuous hairs apothecia. The wall of apothecia frequently consists of 2-3 distinct layers composed of different cell types. Interascal tissue is composed of simple, variously shaped paraphyses, whose apices are sometimes swollen. Asci usually are small, thin-walled, without separable wall layers, and with an apical pore surrounded by a J+ or J- ring. Ascospores usually are small, simple or transversely septate, mostly hyaline, and usually smooth. Anamorphs are hyphomycetous or coelomycetous; many teleomorphs remain with unknown anamorphs.

The order Helotiales is the largest of the orders of inoperculate discomycetes. It consists of 15 families, 372 genera, and 2022 species (Kirk et al. 2001). Many members of Helotiales are saprobes, living on the soil, dead wood, dung, or other material (Alexopoulos et al. 1996). Some are parasites of plants and belong to the worst fungal pathogens. Among them are species of the genera Diplocarpon, Monilinia, Sclerotinia, and Pseudopeziza.

Members of Helotiales has a worldwide distribution.

Hypocreales

The order Hypocreales comprises fungi that form asci with ascospores mainly in perithecia, rarely in cleistothecia. Their ascomata origin either in or on a stroma, are more or less globose, and sometimes ornamented. When present, the ascomatal ostiolum is periphysate. The wall of ascomata usually is brightly coloured. The internal tissue consists of apical paraphyses, which are frequently evanescent. Asci are more or less cylindrical, thin-walled, sometimes with a small apical ring or an apical cap not blueing in Melzer's reagent. Ascospores are hyaline to pale brown, usually septate, sometimes muriform, and occasionally elongate and fragmenting. Anamorphs are hyphomycetous.

The order Hypocreales consists of six families, 117 genera, and 654 species (Kirk et al. 2001). Its most known genera are Claviceps, Cordyceps, Epichloë, Gliocladium, Nectria, and Trichoderma (Alexopoulos et al. 1996; Kirk et al. 2001).

Members of the Hypocreales are saprobes, endophytes, or parasites of plants. Additionally, many are fungicolous or lichenicolous. Few are coprophilous (Alexopoulos et al. 1996; Kirk et al. 2001).

Laboulbeniales

The order Laboulbeniales comprises fungi whose thalli are hyaline to darkly pigmented and associated with Insecta (Alexopoulos et al. 1996; Majewski 1994). The thalli develop from a bicellular ascospore. Thalli of most species have bilateral symmetry. The main axis of a thallus consists of a row of superposed cells originating from the larger cell of the ascospore. Additional divisions of some receptacle cells result in the formation of a perithecium or many perithecia. The perithecia are frequently surrounded by complex appendages. Asci are few, clavate, and thin-walled. Ascospores are hyaline, elongate, spindle-shaped, usually consist of two unequal cells, and are surrounded by a thin sticky envelope that facilities the adherence of the spore to its host body. Anamorphs are hyphomycetous, spermatial, fleeting.

The order Laboulbeniales consists of four families, 141 genera, 1869 species (Alexopoulos et al. 1996; Kirk et al. 2001). All are ectoparasites of Insecta. However, their hosts are only rarely seriously damaged. Not much is known of the host specificity of these fungi (Majewski 1994). Some species of Laboulbeniales have a fairly broad host range, but many are highly host specific (Alexopoulos et al. 1996).

Species of Laboulbeniales are cosmopolitan.

Mycosphaerellales

The order Mycosphaerellales comprises fungi forming small, black, papillate perithecial ascomata with a well developed lysigenous ostiolum. The perithecia are immersed in plant tissue, frequently become erumpent, and are often strongly aggregated or formed on a weakly developed basal stroma. The perithecial peridium usually is thin and consists of pseudoparenchymatous cells. There is no interascal tissue. Asci are ovoid to saccate, fissitunicate, with an ocular chamber, but with no other apical structures, and no reaction in Melzer's reagent. Ascospores usually are hyaline, transversely septate, and have no sheath. Anamorphs usually are hyphomycetous.

The order Mycosphaerellales consists of one family, 10 genera, and 584 species (Kirk et al. 2001). Among them are biotrophic, necrotrophic, and saprotrophic species living on different plant tissues. The most important members of the Mycosphaerellales are those of the genera Ascochyta, Cercospora, Cladosporium, Pseudocercosporella, Ramularia, and Septoria (Kirk et al. 2001).

Pezizales

Fungi of the order Pezizales are frequently called "operculate discomycetes" or "cup-fungi" (Kirk et al. 2001). Their ascomata are apothecial or cleistothecial. They are frequently large, discoid, cupulate, more or less globose, occasionally stalked, and often brightly coloured. The excipulum of the ascomata usually is thick-walled, fleshy or membranous, and consists of pseudoparenchymatous cells. Interascal tissue is composed of simple or moniliform paraphyses, which are often pigmented and swollen at the apices. They are absent in some cleistothecial taxa. Asci are elongated, persistent, thin-walled, usually without obvious apical thickenings. They open by a circular pore (operculum) or vertical split. The ascal wall sometimes stains blue in iodine. In cleistothecial taxa, the asci are globose to subglobose and usually are indehiscent. Ascospores usually are ellipsoidal, aseptate, hyaline to darkly coloured, frequently ornamented, and usually with no sheath. If known, anamorphs are hyphomycetous.

The order Pezizales consists of 15 families, 166 genera, and 1125 species (Kirk et al. 2001).

Fungi of the order Pezizales occupy a wide range of substrates. Among the fungi are saprobes occurring on the soil and very rotted wood, coprophilous taxa, and mycorrhizal fungi.

Pleosporales

Fungi of the order Pleosporales form perithecia or cleistothecia, sometimes clypeate. They are usually more or less globose, black, thick-walled, immersed or erumpent, and open by a well developed lysigenous ostiole, which sometimes is hairy or setose. The ascomatal peridium usually is thick and is composed of pseudoparenchymatous cells. Interascal tissue consists of cellular or trabeculate pseudoparaphyses, frequently immersed in J- gel. Asci usually are more or less cylindrical, fissitunicate, with a well developed ocular chamber, rarely also with a poorly defined ring, not staining in iodine. Ascospores are hyaline to brown, septate, thin- to thick-walled, sometimes muriform, often with a gelatinous sheath. Anamorphs are hyphomycetous or coelomycetous (Kirk et al. 2001).

The order Pleosporales consists of 19 families, 179 genera, and 1447 genera. Members of this order are plant pathogens, saprobes, and lichen-forming fungi. Many species are aquatic in both fresh and marine waters. The most important genera of the Pleosporales are Alternaria, Leptosphaeria, Phoma, Pleospora, Pyrenophora, Septoria, Sphaerellopsis, Spilocaea, and Venturia (Alexopoulos et al. 1996; Kirk et al. 2001).

Taphrinales

Fungi of the order Taphrinales form subcuticular or subepidermal mycelium composed of dikaryotic ascogenous cells (Kirk et al. 2001). Occasionally, they also produce thick-walled, smooth or ornamented resting spores. No ascomata occur. Asci are formed either directly from ascogenous cells or with a separating stalk cell forming internally or in a palisade on the surface of the host tissue. They are more or less cylindrical, rather persistent, and usually 8-spored. Ascospores are hyaline, aseptate, globose or ellipsoidal. Anamorphs are yeast-like, monokaryotic, and form budding ascospores.

The order Taphrinales consists of two families, six genera, and 115 species. Members of this order are biotrophic parasites of a wide variety of angiosperms, causing galls, thickenings, blisters, lesions, and witches' brooms (Alexopoulos et al. 1996)..

The most important genus of this order is Taphrina (Alexopoulos et al. 1996).

Trichosphaeriales

The teleomorphs of the order Trichosphaeriales are superficial, frequently aggregated, more or less globose, black, often thick-walled, usually setose perithecia, whose ostiole are papillate and periphysate. Interascal tissue is composed of narrow, persistent, thin-walled true paraphyses. Asci are cylindrical, persistent, thin-walled, not fissitunicate, frequently with a small J- apical ring. Ascospores are variously shaped, hyaline to versicoloured, usually septate but rarely muriform. They sometimes have polar pores, a sheath, fragment at septa, and have no germ pores. Anamorphs are hyphomycetous, producing simple, pigmented conidiophores, frequently with tretic conidiogenesis and complex conidia.

The order Trichosphaeriales consists of two families, 13 genera, and 51 species. They ar saprotrophs, especially on wood and bark. Other occur on other fungi. Fungi of this order are cosmopolite.

BASIDIOMYCOTA

Ceratobasidiales

Most species of the order Ceratobasidiales have holobasidia that are divided to form four prominent sterigmata or epibasidia. Additionally, they exhibit secondary spore formation and have septal pore caps with large perforations (Alexopoulos et al. 1996).

The order Ceratobasidiales consists of two families, eight genera, and 33 species (Kirk et al. 2001). The best known genera of this order are Ceratobasidium and Thanatephorus.

Taxa of the order Ceratobasidiales occur in the whole world.

Entylomatales

Fungi of the order Entylomatales have simple septal pores with membrane caps. No haustoria are produced. Teliospores are single and poorly pigmented.

The order Entylomatales comprises one family, one genus, and 160 species (Kirk et al. 2001).

Polyporales

Fungi of the order Polyporales form annual or perennial, monomytic or dimitic basidioma with tubulate or lamellate hymenophor.

The order Polyporales consists of 23 families, 288 genera, and 2253 species (Kirk et al. 2001). Among them are saprobes taking place in the degradation of cellulose and lignin, as well as parasites and pathogens of shade and forest trees (Alexopoulos et al. 1996).

Uredinales

Fungi of the order Uredinales are commonly called "rust fungi" or "rusts". The generally form intercellular mycelium without clamp connections and frequently with haustoria (Kirk et al. 2001). In local infections, the occurrence of the mycelium is limited to leaves or other aerial organs of the host. In systemic infections, the mycelium overwinters in roots or other overwintering plant organs.

Most rust fungi exhibit complicated life cycles, typically involving two taxonomically unrelated plant hosts and the production of up to five spore states, frequently numbered 0-IV, where 0 - refers to spermogonia bearing spermatia, I - aecia bearing aeciospores, II - uredinia bearing urediniospores, III - telia bearing teliospores, and IV basidia bearing basidiospores (Alexopoulos et al. 1996; Kirk et al. 2001; Majewski 1979).

Aeciospores are produced in aecia, are unicellular, non-repeating vegetative spores, and usually dikaryotic. They germinate to form dikaryotic mycelium. Aeciospores usually are catenulate, thin-walled, and verrucose. However, they sometimes resemble urediniospores, and then are named "uredinioid aeciospores".

Urediniospores, frequently called "summer spores" or "red rust spores", are repeating vegetative spores, produced on dikaryotic mycelium in uredinia. Typical urediniospores are unicellular, short-lived spores, have a pedicel, and a pigmented wall with two or more germ pores. When they resemble typical aeciospores, they are called "aecidioid urediniospores".

Teliospores, also called "winter spores" or "black rust spores", produce basidia with basidiospores. Teliospores are produced in telia. Telia and teliospores represent the teleomorph of rust fungi. Teliospores are resting, long-lived, thick-walled spores. Their wall may be variously ornamented. They rarely resemble typical aeciospores, and then they are called "aecidioid teliospores".

Basidiospores, occasionally called "sporidia", are haploid, unicellular, thin-walled, and short-lived spores. They are produced on a 2-4-celled metabasidium (promycelium) after meiosis and liberate from its sterigmata by abjection.

However, not all rust fungi produce all the states listed above. Therefore, species of the Uredinales are divided into three categories: (1) macrocyclic forms that produce all five reproductive states, (2) demicyclic forms which lack a uredinial state, and (3) microcyclic forms in which both aeciospores and urediniospores are absent and the teliospore is the only binucleate spore produced. In some taxa, spermogonia may occasionally be absent.

When a rust fungus life cycle takes place on one host or a group of closely related hosts, the fungus is called "autoecious". When spermogonia and aecia develop on one host and telia origin on another host, the fungus is heteroecious.

Rust fungi may be heterothallic or homothallic. Heterothallic macrocyclic species produce basidia with two (+) or two (-) basidiospores. A (+) or (-) basidiospore infects the right host, forms a haploid mycelium, then spermogonia with (+) or (-) spermatia, and finally protoaecia (initial aecia with no aeciospores). Subsequently, spermatia are transferred, usually by insects, on (+) or (-) receptive hyphae of spermogonia, their nuclei go into the hyphae, multiply, and migrate downward into the aecial initials. Finally, some of the aecial initial cells are dikaryotized and the aecia start to produce aeciospores. After infection of plants by aeciospores, uredinia with urediniospores origin. The aeciospores and their mycelia, as well as the urediniospores and their mycelia are dikaryotic. In teliospores and basidia, nuclear fusion and meiosis take place, respectively.

In homothallic rust fungal species, spermogonia are not needed or are not formed at all to complete their life cycles. The dikaryophase begins from two cell nuclei at some point or points of their life-cycle. Then, nuclear fusion and reduction proceed, identically as in heterothallic species.

The order Uredinales comprises 14 families, 163 genera, and 6929 species (Kirk et al. 2001). They are generally considered obligate parasites, although growth of Gymnosporangium juniperi-virginianae Schw. in axenic culture has been reported (Kirk et al. 2001).

Fungi of the Uredinales are economically among the most important of all species of the phylum Basidiomycota (Alexopoulos et al. 1996; Majewski 1979). Among the most harmful representatives of this order are species of the genera Cronartium, Gymnosporangium, Melampsora, Phragmidium, Puccinia, and Tranzschelia. The harmfulness of rust fungi also results from their ability to form so called "special forms" or "formae speciales".

Urocystales

Fungi of the order Urocystales form conglomerations of spore balls in different organs of their plant hosts. The spore balls are usually produced in leaves and stems that, thereby, become thickened, deformed, and finally irregularly crack. The spore balls are permanent and consist of an outer layer of lighter coloured, sterile cells that surround one or more darker coloured teliospores. Only the teliospores may germinate to form metabasidia (promycelia). Prior to germination, the diploid nucleus of a mature teliospore undergoes meiosis. Following zero to two synchronous mitotic divisions, the haploid nuclei migrate into the metabasidium. In contrast to species of the order Ustilaginales, the metabasidium of the Urocystales is aseptate. Then, many basidiospore initials, usually eight, are formed at the tip of the metabasidium. Finally, a nucleus earlier formed in the metabasidium moves into a basidiospore initial. Once a nucleus has entered a basidiospore initial, it divides mitotically and one of the daughter nuclei moves back into the metabasidium. Infection of a plant host is conditioned by the formation of a binucleate mycelium. The binucleate mycelium origins after copulation of two compatible basidiospores, i. e., spores of different mating types (Alexopoulos et al. 1996).

Members of the order Urocystales forms intracellular haustoria.

The order Urocystales consists of two families, six genera, and 26 species (Kirk et al. 2001). Some of them are sometimes destructive plant pathogens and are widely distributed in the world, as, e.g., Urocystis cepulae Frost and U. occulta (K. F. W. Wallroth) L. Rabenhorst ex L. Fuckel.

Ustilaginales

The order Ustilaginales includes the plant pathogenic fungi commonly known as the smut fungi. This name comes from the black, dusty masses of teliospores resembling soot or smut formed in diseased plants (Alexopoulos et al. 1996). The teliospores are thick-walled probasidia produced in sori on living plants. Upon germination, the probasidia give rise to non-septate or transversely septate metabasidia (promycelia), from which haploid ballisto- or statismospores origin (Kirk et al. 2001).

The order Ustilaginales consists of one family, Tilletiaceae, 33 genera, and 493 species (Kirk et al. 2001).

Members of the Ustilaginales are facultative saprobes. On culture media, the teliospores germinate to form mycelium and/or yeast-like spores.

The smut fungi attack ca. 4000 species of angiosperms belonging to over 75 families (Alexopoulos et al. 1996). Most of them are host-specific endophytes and parasitize on flowering plants, especially of the families Cyperaceae and Poaceae. Sori are commonly limited to the ovary, anthers, inflorescence, or leaves and stems of the hosts, although roots are also attacked. Three types of infection of plants by smut fungi have been recognized: (1) seedling infection from teliospores present on the seed, (2) seedling infection by mycelium present in the seed as a result of teliospore germination on the stigma at flowering time, and (3) infection by wind-borne sporidia coming from metabasidia present among decaying plant material.

Although some species of the order Ustilaginales are confined geographically to small areas, others occur wherever their hosts grow.

Tilletiales

Fungi of the order Tilletiales mainly form spores in pistils of plants of the family Poaceae, rarely in leaves (Kochman 1986). The spores are darkly coloured and usually are more or less agglutinated. Most species of this order form spores ornamented with a net. Other characters of these fungi are as those of species of the order Urocystales (see above).

The order Tilletiales consists of one family, Tilletiaceae, seven genera, and 179 species (Kirk et al. 2001). One of the most destructive plant pathogens widely distributed in the world is Tilletia caries (A. P. de Candolle) L. -R. & C. Tul., causing bunt or stinking smut of wheat.

GLOMEROMYCOTA

The phylum Glomeromycota C. Walker & Schuessler comprises arbuscular mycorrhizal fungi (AMF; Schüßler et al. 2001). Walker and Schüßler and Walker's (2001) molecular investigations indicated that arbuscular fungi are more closely related to fungi of the phyla Ascomycota and Basidiomycota than to members of the phylum Zygomycota, as, e.g., Gerdemann and Trappe (1974) and Morton and Benny (1990) believed.

The Glomeromycota consists of four orders, i. e., Archaeosporales C. Walker & Schuessler, Glomerales Morton & Benny, Paraglomerales C. Walker & Schuessler, and Diversisporales C. Walker & Schuessler belonging to the class Glomeromycetes Cavalier-Smith.

Arbuscular mycorrhizal fungi co-exist in an obligatory symbiosis with at least 80% of land plants (Gianinazzi and Gianinazzi-Pearson 1986). This symbiosis is called arbuscular, because the only structure produced within root cells by members of seven of the eight genera of the phylum are arbuscules, i. e., finely branched haustorium-like hyphal branches, which take part in a bilateral exchange of carbon, phosphorous, and other physiologically important elements (Smith and Read 1997).

Yet not long ago, only the families Brassicaceae and Chenopodiaceae have been considered to comprise a relatively large number of plant species that are non-mycorrhizal or infrequently co-exist with AMF (Gerdemann 1968; Harley and Harley 1987, 1990). However, the results of recent studies indicate that mycorrhizae formed by some species of AMF do not react in commonly used stains (Morton and Redecker 2001) and a large part of AMF of different ecosystems do not sporulate at all or sporulate seasonally in the field (Blaszkowski et al. 2002a, b; Stutz and Morton 1996). This may have been the reason of the erroneous conclusions of the mycorrhizal status of many plant taxa and, thereby, supports the statement expressed by the Committee of the International Bank for the Glomeromycota in 1993 that “The majority of plants, strictly speaking do not have roots; they have mycorrhizas”.

Literature data indicate that AMF increase the root absorptive area and hence the plant nutrition (Bieleski 1973), influence succession of plant communities (Janos 1980), their competitiveness (Allen and Allen 1984; Fitter 1977) and phenology (Allen and Allen 1986), equalize the level of nutrition of co-existing plants by formation of hyphal bridges transferring nutrients between them (Newman 1988) and improve soil structure through binding sand grains into aggregates by extraradical hyphae (Koske et al. 1975; Sutton and Sheppard 1976). Additionally, AMF increased the tolerance of plants to heavy metals (Dehn and Schüepp 1989; Griffioen and Ernst 1989), water stresses (Stahl and Smith 1984), as well as to pathogenic fungi and nematodes (Schönbeck 1978).

This website shows only a few species of arbuscular fungi deposited in the Department of Plant Pathology, University of Agriculture in Szczecin. All the species collected are presented in a website entitled ”Arbuscular mycorrhizal fungi (Glomeromycota), Endogone, and Complexipes species deposited in the Department of Plant Pathology, University of Agriculture in Szczecin, Poland". Address: http://www.agro.ar.szczecin.pl/~jblaszkowski/.

Archaeosporales

The fungi of the order Archaeosporales form endocytosymbioses with photoautotrophic prokaryotes [Geosiphon pyriformis (Kütz.) Wettstein emend. Schüßler] or produce mycorrhizae with arbuscules, with or without vesicles. Their spores are colourless and do not react in Melzer’s reagent. Glomoid spores (identical to those of fungi of the genus Glomus) form singly or in clusters on or under the soil surface. Acaulosporioid spores (similar to those of members of the genus Acaulospora) develop singly in the soil. The fungi differ from other arbuscular fungi by the possession of the rRNA SSU gene signature YCTATCYKYCTGGTGAKRCG, corresponding to homologous position 691 of the Saccharomyces cerevisiae SSU r RNA sequence J01353, with the coloured nucleotides being specific for the taxon. The order Archaeosporales contains two families, Archaeosporaceae with the genus Archaeospora, and Geosiphonaceae Engler et Gilg emend. Schüßler with the genus Geosiphon (Kütz.) v. Wettstein.

Diversisporales

Members of the order Diversisporales form mycorrhizae with arbuscules, frequently lacking vesicles, with or without auxiliary cells. Spores develop either inside (entrophosporioid spores of the genus Entrophospora) or laterally on the neck of a sporiferous saccule (acaulosporioid spores of the genus Acaulospora), from a bulbous base on the sporiferous hypha (gigasporioid spores of the genera Gigaspora and Scutellospora), or blastically at the tip of a sporogenous hypha (glomoid spores of the genus Diversispora). They differ from other arbuscular fungi by the possession of the rRNA SSU gene sequence signature YVRRYW/1-5/NGYYYGB, corresponding to homologous position 658 of the S. cerevisiae SSU rRNA sequence J01353 SSU rRNA, and GTYARDYHMHYY/2-4/GRADRKKYGWCRAC, corresponding to homologous position of the S. cerevisiae SSU rRNA sequence position 1346 of the S. cerevisiae SSU rRNA sequence J01353, with the coloured nucleotides being specific for the taxon. The order Diversisporales is represented by three families, Diversisporaceae with the genus Diversispora, Acaulosporaceae with the genera Acaulospora and Entrophospora, Gigasporaceae with the genera Gigaspora and Scutellospora, and Pacisporaceae with the genus Pacispora.

Glomerales

Fungi of the order Glomerales usually are hypogeous, rarely epigeous. They produce mycorrhizae with arbuscules, vesicles, and spores. Spores form either blastically at the tip of a sporogenous hypha or intercallarly inside them. Spores occur singly, in clusters or sporocarps having a peridium. They differ from other arbuscular fungi by the possession of the rRNA SSU gene sequence signature YTRRY/2-5/RYYARGTYGNCARCTTCTTAGAGGGACTATCGGTGTYTAACCGRTGG, corresponding to homologous position 1353 of the S. cerevisiae SSU rRNA sequence J J01353, with the coloured nucleotides being specific for the taxon. The order Glomerales includes one genus, Glomus.

OOMYCOTA

Peronosporales

Members of the order Peronosporales form coenocytic intercellular mycelium with haustoria (Kirk et al. 2001). The haustoria of species of Albugo are small, spherical structures, whereas those of Peronospora species are more elongate. Except for species of the genus Peronospora producing conidia, the other taxa of this order reproduce by reniform and biflagellate zoospores. Sexual reproduction in the Peronosporales is by means of oospores originated from oospheres formed in an oogonium fertilized by nuclei in an antheridium borne on the same or on different hyphae. The oospore wall is thick and either smooth or ornamented; it may be spiny, warty, wavy, ridged, or otherwise marked.

The order Peronosporales consists of two families, Albuginaceae and Peronosporaceae, nine genera, and 252 species (Kirk et al. 2001). The classification of the Peronosporales is based mainly on the characters of sporangia and sporangiophores (Alexopoulos et al. 1996).

Members of the Peronosporales are the most specialized microorganisms of the phylum Oomycota (Alexopoulos et al. 1996). Among them are aquatic, amphibious, and terrestrial species, being highly specialized obligate parasites. Many species of this order are serious pathogens of a number of economic plants, frequently causing epidemics.

Members of the order Peronosporales are cosmopolite.

Pythiales

Members of the order Pythiales have mycelial or pseudomycelial thallus (Kirk et al. 2001). The mycelium is well developed and haustoria are produced in some species. The microorganisms reproduce asexually by sporangia or conidiosporangia. The hyphae that bear the sporangia or conidiosporangia usually are indistinguishable from the mycelium, except for some species in which definite sporangiophores are formed. Sexual reproduction takes place by thin-walled oogonia, resulting in the formation of oospores. Oospores usually are single. Their walls almost always are smooth.

The order Pythiales consists of two families, 11 genera, and 100 species (Kirk et al. 2001). The most important and common taxa of this order are those of the genera Phytophthora and Pythium (Alexopoulos et al. 1996).

ZYGOMYCOTA

Endogonales

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.

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 one of the authors of this website, J. Blaszkowski, 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 J. Blaszkowski, 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.

ANAMORPHIC FUNGI

In the literature, different names for the anamorphic fungi are used, e.g., Deuteromycotina, Deuteromycetes, Fungi Imperfecti, asexual fungi, conidial fungi, or mitosporic fungi. These fungi produce propagules from cells where no meiosis occurs. Most of these propagules are called "conidia". Many anamorphic fungi are asexual states of taxa recognized to form spores from cells where meiosis takes place or is assumed to occur (i. e., the teleomorph). If recognized, most of them are members of the phyla Ascomycota and Basidiomycota. Some anamorphs are considered to have lost sexuality and it is replaced by, e.g., the parasexual cycle. Now, molecular techniques make possible to place anamorphic fungi with their unrecognized sexual states with the groups of teleomorphic fungi from which they are or once were derived.

Based on morphological characters of the structures producing conidia, three groups of anamorphic fungi are segregated: (1) hyphomycetous anamorphic fungi with mycelial forms bearing conidia on separate hyphae or aggregations of hyphae (as synnematous or sporodochial conidiomata), but not inside discrete conidiomata; (2) agonomycetous anamorphic fungi with mycelial forms which are sterile, but may produce chlamydospores, sclerotia, and/or other related structures; and (3) coelomycetous anamorphic fungi producing conidia in pycnidial, pycnothyrial, acervular, cupulate, or stromatic conidiomata.

Anamorphic fungi occupy a wide range of different habitats (Alexopoulos et al. 1996). Most of them are terrestrial, although many species occur in marine and freshwater habitats. The majority of anamorphic fungi are either saprobes or weak parasites of plants. However, many species can cause serious diseases of plants and animals. A few species trap and consume nematodes. Others are lichen symbionts, endophytes, and form mycorrhizae. Many taxa parasitize on other fungi and lichens. Some members of this group of fungi are used in the production of certain chemicals, e.g., some antibiotics, and in processing and flavouring foods. Finally, still others poison foods.

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