Q.Write short notes: Useful Fungi.

Kingdom Fungi comprises eukaryotic heterotrophs with extracellular digestion, typically found in warm, humid places. Their body is either unicellular or built of thread-like hyphae forming a mycelium, which may be septate or non-septate (coenocytic, multinucleate); the fungal cell wall is made of chitin. Fungi reproduce both sexually and asexually (fragmentation, fission, budding) and are mostly saprophytic, though some are parasitic or predatory; some form symbioses — with algae as lichens, or with plant roots as mycorrhiza. They are classified into four groups: Phycomycetes ("algal fungi," aseptate coenocytic hyphae, e.g. Mucor, Rhizopus, Albugo); Ascomycetes ("sac fungi," branched septate hyphae, e.g. Aspergillus, Penicillium, Claviceps, Neurospora, Saccharomyces); Basidiomycetes ("club fungi," e.g. Agaricus, Ganoderma, Ustilago, Puccinia); and Deuteromycetes ("imperfect fungi," reproducing only asexually, e.g. Alternaria, * …