Aquatic hyphomycetes

Aquatic hyphomycetes live in aquatic habitats, most known from well-aereated freshwater streams on leaf litter and other decaying plant material, but they are also found in ponds, lakes, estuarine and marine environments. They are primarily saprotrophs, and break down leaves, or wood, together with bacteria, and other organisms such as oomycetes. This decomposition makes nutrients available for other organisms that can't break down or use these nutrients on their own. They therefore facilitate for other organismsfor example groups like benthic insects eating leaves "conditioned" by fungi and bacteria. Some species have also been observed as being endophytes in the roots of riparian plant species, and other species are observed to be mycoparasites. Historically, many species have gotten their own Latin nameseven without the sexual stage being known. However, in more recent times, some species have gotten their sexual stage identified via molecular methods. One such example is Articulospora tetracladia being identified as the previously described Hymenoscyphus tetracladius. == History ==

The first aquatic hyphomycete that is in this ecological group that was described was Heliscus lugdunensis (Neonectria lugdunensis), described by Pier Andrea Saccardo and Jean-Jacques Therry, indexed andpublished by Saccardo in 1880. The second to recognize and describe three species from this group was Émile De Wildeman in the 1890s. The first one to recognize and describe the ecological group in their enviromnment, however, was Cecil Terence Ingold in 1942, where he described many species from decaying alder leaves in a stream in England. Since then hyphomycetes have been observed from all around the world. Many species were long thought to be cosmopolitan, but recent phylogeny on biogeography of species seem to counteract this thought. == Identification ==

Identification of these species is based mainly on spore morphology. Spores usually have tetraradiate, scolecoid, or filamentous shapes. Some important characters for identification include: number, and placement of septa; branches; constrictions at the septa; spiny tips of branches; length and width of branches, with more. The hyphae extends a conidiophore from the substrate and develops a conidia that breaks off into the stream, to find a new substrate, attach, and germinate. These spore morphologies are believed to be specialized to survive in stream environments, and attach to specific substrata, which gives them their shapes. For many species the spore morphology is not enough, however, and the structure of the conidiophore is required. This is most often done by getting the fungi to grow in cultures, and then inspecting the spore-producing structures. Key characters to look out for when identifying aquatic hyphomycetes are • Amount of elements in the conidium. • Constrictions at the bases of secondary or tertiary elements. • Scar location and form. • Shapes of the endings of elements. • Shapes, and measurements of the elements. • Amount of septa. • Curvature of main axis. == References ==