*A spreadsheet showing all of the name changes that have occurred since the printing of Mushrooms of the Redwood Coast can be found here: 

MoRC Nomenclatural Changes (last updated 26 February 2018)

The Naming of Creatures: A Necessary Mess
Humans use common names (those in vernacular languages  – English, Spanish, Hindi, etc.) as well as scientific names (in quasi-Latin or Greek) to communicate with one another about living organisms. 

Common names are in many instances very useful because they tend to be much easier for most people to remember, are often more pronounceable to speakers of that language. They are often charismatic, humorous, or obviously descriptive in ways that scientific names sometimes fail to achieve. They also have the advantage of not needing to mirror taxonomic changes (those that come from newer or updated understanding of evolution), and thus can feel more stable. However, this can be a downside for those folk who are interested in learning which organisms are related to each other. Likewise, common names inherently differ between different languages, and can even have many dramatically different names in use among the  speakers of a single language.

Scientific names are extremely valuable for many reasons, including that they help to reduce some of the confusion that arises from using common names. They are intended to help folks refer to a species with a single, standardized name no matter what language the communicators might speak otherwise. Towards this end, scientists have formalized the way they name organisms. One way this has been achieve is to use "Latinized" words, which are intended to level the playing field among different language speakers. There are obviously problems with this (for example, speakers of Latin-derived languages have a much easier time with them, as well as the fact there are no rules against introducing totally non-Latin vocabulary into scientific names). There are other difficulties that arise from this method as well – names can be complicated and awkward, difficult to pronounce, poorly descriptive of the species they are assigned to, etc.

          However, the problem that most people have with scientific names is that they seem to be constantly changing (see Reasons that Names Change below). For a lexicon that was explicitly intended to provide stability, this instability is a real problem. An optimistic view of the situation suggests that as connectivity between researchers increases and their methods become more sophisticated, the future will see an ever-declining rate of name changes... A realistic addendum would note that we’re still in the midst of a high rate-of-change, and are likely to be so for quite some time.

The goal is to establish one (1) scientific name for each species, and to consistently use that name.

This goal is far, far easier said than done. One of the most intractable problems is that no one is exactly sure what a “species” is. There are many definitions, some of them competing. The most commonly used paradigm is the Biological Species Concept (BSC), which states that any two individuals that can breed with one another and produce viable offspring can be said to pertain to the same species. This is really useful if you can test it, and if you can’t it’s of limited utility. And, for a variety of reasons, it’s a very difficult model to put to the test for mushrooms.

We struggle along, as best we can. And in general, things are getting better. Not necessarily easier to remember or implement, but at least more reflective of biological realities, and more stable from year to year. Mostly.

Reasons that Names Change
Splits – this is relatively straightforward to understand.
Sometimes we find out that there is more than one species going by the same name, and they need to be split into two species, each with their own name. This is quite common.
Lumps – also relatively straightforward. Sometimes scientists end up having given two different names to different-looking forms of the same variable species.
Systematic changes
Nomenclatural bureaucracy