Freshwater Mitosporic Fungi

This database provides information on mitosporic fungi from various lotic (running waters, eg. rivers and streams) and lentic (standing waters, eg. bogs, lakes, ponds, and swamps etc.) freshwater habitats. Substrates, geographical distribution, ecoclimatic zones, and literature citations for each species record are given. The database of mitosporic fungi is exclusive of the hyaline aquatic ingoldian and aeroaquatic fungi.

This database is complied and maintained by Huzefa A. Raja and Carol A. Shearer, Department of Plant Biology, University of Illinois at Urbana Champaign. This material is based upon work supported by the National Science Foundation under Grant No. 0316496. 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.

The list of species available on this website although comprehensive is by no means complete, and there are several very early publications that need to be checked. This database is updated annually with respect to new literature. For comments, and additional information contact Huzefa A. Raja at raja@life.illinois.edu

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INTRODUCTION

The mitosporic fungi are a group of fungi that consists of asexual states of mostly ascomycetes and some basidiomycetes. The mitosporic fungi undergo mitotic division to produce microscopic asexual structures called conidia, which are of various colors, sizes, shapes, and septations. The mitosporic fungi are also traditionally referred to as fungi imperfecti, anamorphic fungi, or the form taxon Deuteromycotina (Seifert and Gams, 2001). Ascomycete fungi are commonly referred to as sac or pouch fungi because they carry most commonly eight or sometimes more than eight microscopic ascospores within a meiosporangium termed as an ascus (Barr, 2001). The ascospores are products of meiosis, hence they are called meiospores. Therefore, an ascomycete fungus in its lifetime can reproduce sexually by producing meiospores (ascosopores) as well as asexually by producing mitospores (conidia) or by producing only meiospores (ascospores) or only mitospores (conidia).

The mitosporic fungi are classified into two main classes, namely hyphomycetes, and coelomycetes. The hyphomycetes produce conidia directly from vegetative structures (hyphae) or on distinct conidiophores (a specialized hypha that bears conidiogenous cells and conidia) whereas, the coelomycetes produce conidia within asexual fruit bodies called pycnidia.

The freshwater mitosporic fungi are classified into three ecological groups namely; the Ingoldian hyphomycetes also known as the aquatic hyphomycetes, aeroaquatic hyphomycetes, the dematiaceous (dark colored) and hyaline (light colored) hyphomycetes and coelomycetes.

BACKGROUND

Ingoldian Hyphomycetes

The aquatic hyphomycetes were first recognized by Ingold (1942) and are also referred to as the Ingoldian hyphomycetes in his honor. The Ingoldian hyphomycetes form a poylphyletic group with representatives in the Ascomycetes and the Basidiomycetes. The aquatic fungi are also called as freshwater hyphomycetes (Nilsson, 1964), water borne hyphomycetes (Webster and Descals, 1981) or amphibious hyphomycetes (Akridge and Koehn, 1987). The Ingoldian hyphomycetes produce conidia that are mostly unpigmented and branched or long and narrow. These conidial types are adapted for life in running water (see Ingold, 1953, 1956, 1966, 1975, 1984; Webster, 1981; Read, 1990; Goh and Hyde, 1996; Wong et al., 1998 for more detailed explanations). The Ingoldian hyphomycetes most commonly occur on dead leaves (Webster and Descals, 1981; Baerlocher, 1992) and wood (Willoughby and Archer, 1973; Sanders and Anderson, 1979; R_vay and G_ncz_l, 1990; Shearer and Webster, 1981; Shearer, 1992) as well as in foam (Iqbal and Webster, 1973; Iqbal, 1995) in streams and rivers surrounded by dense vegetation. A few species have also been reported from well aerated lakes and ponds as well as within tree holes (G_ncz_l and R_vay, 2003,). They mediate energy flow and nutrient cycling in streams (Baldy et al., 1995) and act as intermediaries of energy flow between leaf litter and invertebrates (Baerlocher and Kendrick, 1976; Suberkropp, 1992). So far about 290 species are reported from leaves and wood in freshwater habitats worldwide (Shearer et al. unpublished). Marvanova and Descals (unpublished) will provide more detailed information on the ecology, taxonomy, and distribution of Ingoldian hyphomycetes in their monograph.

Aeroaquatic Hyphomycetes

The aeroaquatic hyphomycetes were first termed by van Beverwjik (1951 a, b; 1953; 1954). Later Fisher (1977) defined them as indewelling organisms characterized by the production of purely vegetative mycelium in substrates under water and formation of conidia with special flotation devices, formed only when the substrates on which the fungus is growing are exposed to a moist environment. These fungi are usually found in stagnant ponds, ditches, or slow flowing water and are capable of vegetative growth on submerged leaves and woody substrates under semi-anaerobic conditions. Thus far, about 90 species have been reported from leaves and wood in freshwater lotic and lentic habitats worldwide (Shearer et al. unpublished). Voglmayr provides more information about the Ecology, biodiversity and distribution of aeroaquatic fungi on the webpage http://www.botanik.univie.ac.at/mycology.

Dematiaceous and Hyaline Mitosporic Fungi

These fungi include species of dematiaceous and hyaline hyphomycetes and coelomycetes (Goh and Hyde, 1996) exclusive of aeroaquatic and hyaline aquatic Ingoldian hyphomycetes. The conidia of this group are not distinctively modified for the aquatic environment unlike the above mentioned groups. The fungi occur mainly on decaying herbaceous plant material and woody debris in aquatic and semi aquatic habitats worldwide. Submerged wood debris supports a higher species diversity of dematiaceous and hyaline mitosporic fungi, although this may reflect a lack of study of herbaceous debris using techniques that would facilitate the discovery of species in this group. Four hundred and fifty species of dematiaceous and hyaline mitosporic fungi have been reported from freshwater habitats worldwide.

Dematiaceous and hyaline mitosporic fungi can be classified into two main types based on Park (1972), namely indwellers and immigrants. Species in several genera of freshwater mitosporic fungi like Aquaphila, Canalisporum, Camposporidium, Candelosynemma, Clohesyomyces, Conioscyphopsis, Elagantimyces, Enridescalsia, Jeranium, Nidulispora, Paracryptophiale, and Yinmingella etc. can be classified as indwellers because they have been reported only from freshwater habitats. Whereas, species that belong to genera such as Acrodictys, Acrogenospora, Arthrobotrys, Bactrodesmium, Berkleasmium, Brachysporiella, Brachysporium, Camposporium, Cordana, Conioscypha, Dactylaria, Dictyosporium, Ellisembia, Exserticlava, Monodictys, Neta, Spadicoides, Sporidesmiella, Sporoschisma, Taeniolella, Trichocladium, Vanakripa, and Xylomyces can be classified as immigrants because they are reported from terrestrial as well as freshwater habitats. Tsui and Goh (2004) provide a key to some common genera of dematiaceous mitosporic fungi that have been reported from freshwater habitats worldwide.