Descriptions of fungus species recorded only what could be seen with the naked eye. After microscopes became common, precise descriptions of spores became a necessary part of a species description. With each advance in investigation, the amount and kind of information that is considered an adequate description of a species changes. Specialists borrow collections of accepted species to re-study them and incorporate new data into their descriptions. Revised descriptions provide a more accurate portrait of a fungus species as a unique organism.
Collections are just as valuable for their potential information.
Today, the DNA extracted from their collections helps increase our understanding of how different species of fungi are related to each other. Those earlier mycologists could not have imagined that some species of fungi would become extinct or endangered due to global warming, pollution or the destruction of their habitat. Today, their collections can be used to make lists of species that no longer exist, aid in the reconstruction of the biota of a destroyed habitat, or provide a record of the changes over time in the fungi growing in a habitat. As new methods of investigation are discovered, the record of identity, time and place contained in research collections will continue to result in new information. Herbaria were first established in the 15th century as a reference and teaching tool for the medicinal gardens of monasteries.