Over roughly the past two hundred years mycologists have been using observation, measurements, chemical tests and microscopes to help identify and describe fungi. Our taxonomic systems have been refined through accumulating knowledge of their habitats, modes of nutrition, and reproductive lives, and more recently by a surging interest in understanding how all life forms manage to compete over many hundreds of millions of years for survival amid both gradual and catastrophic geological and meteorological movements. "Sudden" changes, such as the impact of a meteor on earth that hit in the ocean off Mexico, wiped out the impressively diverse and often large species of dinosaurs. At the same time, these changes created conditions that permitted the subsequent proliferation and spread of small land mammals that in time came to dominate the earth. This meteor event caused widespread extinctions, but it also provided surviving plants, fungi and animals countless opportunities to succeed through morphological diversification of species adapted to varied habitats and successful reproductive strategies.

 

Most amateur and professional students of mycology agree that the fungi we find in our forests, parks and yards today are probably morphologically different from their counterparts living many millions of years ago. But we generally have tended to think of any fungal and plant species as static entities existing at this moment in time and not necessarily connected. Our fungal taxonomic systems reflected our trust in the belief that fungi sharing similar morphological characteristics were closely related. However, we are learning that some fungi that we group together based on their similar structures are not as closely related to each other as we have assumed for the past couple of hundred years. Some of these are, in fact, rather distantly related. And some fungi that don’t look anything alike are actually more closely related than are fungi that do look similar.

 

At the same time, we are realizing that many of the European names North American mycologists adopted for our similar mushrooms are genetically different. They may once have been genetically the same, but over the course of tens of thousands, hundreds of thousand or millions of years they have changed enough to to be considered unique species – often adapted to entirely different habitats than their look-alikes living elsewhere in the world. We are also discovering that at least some of the mushrooms we first learned to identify with confidence are a not single species or even a variation of a single species. What we having been calling Amanita vaginata, for example, appears to actually be a complex of different species. The same goes for many other fungi. Such discoveries have necessitated not only a change in a given fungi’s order and/or family or genus, but also changes in their names. In many cases, names for unidentified species must first be determined and then accepted by mycologists. This process is done in accordance with the rules devised by the International Code of Botanical Nomenclature (ICBN). Nowadays DNA sequencing is being harnessed as the latest tool for identifying fungi and their phylogenetic relationships.The upshot is that while many of our taxonomic groupings continue to be useful for field identification, the implication that they represent evolutionary developments among fungi in their respective groupings does not always hold up to scrutiny.

 

For a range of good reasons, many field mycologists and authors have not been entirely eager to adopt the flood of new names and taxonomic changes that have upset our ideas regarding logical relationships. After all, who wants to bother to learn new names? Anyway, it is argued, amateurs only want to be able to identify fungi so they can avoid poisoning themselves while providing food for the family table. Field guides are sensibly arranged into a few general morphological groups, such as the cap and stem agarics, the corals, the crusts, the jelly fungi, the puffballs, the polypores, and so on. Someday we may have field guides that arrange all included fungal species phylogenetically, and we will have a lot more to learn than just new names. And as techniques improve for assessing phylogenetic relationships, we will all eventually embrace the changes that are taking place in all the divisions and kingdoms.

 

Darwin, were he alive today, would no doubt be delighted that we are finally prepared to accept that fungi, just like other living organisms, are not static. They are constantly evolving and adapting to large scale environmental challenges typically occurring over millions of years brought on by loss or gain of habitat due to the earth’s cycles of heat and cold, changing oxygen and water levels, continental drift, massive extinction of species, and so on.

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Mycology evolves, too. Someday we will be able to more or less accurately describe the environmental and atmospheric conditions under which particular morphologies arose. We will know more about fungal chemistry, food sources, connections with plant roots and the other hidden creatures in the soil. We will gain more understanding about how these creatures, including bacteria, insects, worms, and nematodes, compete and "wheel and deal" with fungal mycelia for limited resources. We should also be able to predict with accuracy the types of mushrooms that may evolve under similar conditions in the future.