Phospholipid-derived fatty acids microbial classes when in fact those PLFAs are present in a broad range of life forms. Phospholipids can occur in many biological classes (such as in plant roots, fungi, as well as in soil bacteria), so care has to be taken in over-assigning PLFA biomarkers to the wrong class. Even though phospholipids occur in many different life forms, the fatty acid side chains between differing life forms can be quite unique. Polyunsaturated fatty acids ("e.g." 18:3 ω3c) are found in plants, algae and cyanobacteria, but are often not present in bacteria. Monounsaturated fatty acids (particularly at the omega-7 position), odd-chain
Gasteroid fungi described by Linnaeus in his original "Species Plantarum" of 1753, but the first critical treatment of the group was by Christiaan Hendrik Persoon in his "Synopsis methodica fungorum" of 1801. Until 1981, this book was the starting point for the naming of Gasteromycetes under the "International Code of Nomenclature for algae, fungi, and plants". Although the starting point was subsequently put back to 1753, names of gasteroid fungi used in Persoon's book are still sanctioned and cannot be replaced by earlier names. Elias Magnus Fries introduced the name Gasteromycetes for a class of fungi in his "Systema Mycologicum" of 1821,