ABSTRACT
The cells of all fungi are enclosed in a cell wall that is permeable to gases and dissolved solutes. The nutritional requirements of fungi are met through several different kinds of interactions with their surroundings and other organisms. The yeasts are an alternate growth form that occurs in some fungi that are essentially metabolically active spores. The characteristic structure associated with the sexual stage of fungi in the phylum is the zygospore. An example of a classification system that is employed in the identification of anamorphic fungi that continues to be useful (even though it may not reflect the “true” holomorphic identity of the fungi that are organized within it) relates to the organization of the conidia-forming hyphae (conidiophores). Lichens consist of a biotrophic relationship between a fungus (almost always a member of the Ascomycota, although a very small number of Basidiomycota are also involved) and an “alga” that is either one of the Cyanobacteria or one of the Chlorophyta.
