just some nomenclatural dots on the i here.
Agaricus ponderosus Peck was an illegitimate name – it was validly (according to the rules at that time) described.
Saccardo moved Agaricus ponderosus Peck into Armillaria, but, as Agaricus ponderosus Peck is illegitimate it became Armillaria ponderosa Sacc. and is a synonym of A. magnivelaris Peck.
But is the Eastern species a genetic match for the brown species in Japan? If not, what do we call that one?
Here is something I just posted on the FFSC email group about this subject
Here is more about this subject, taking from the forthcoming book, Mushrooms of the Redwood Coast.
“To get to the bottom of the names used for this fungus is a little complicated:
The Matsutake was described by Peck from upstate New York in 1873 as Agaricus ponderosus (most gilled fungi were still called Agaricus back then). This was an invalid name because it was previously used for a different species. In 1878 he re-described it as Agaricus magnivelaris. In 1887 Saccardo described Armillaria ponderosa, which was a valid name, and one that was commonly used into the 1990s. Even though Singer placed it into Tricholoma (=T. ponderosum) in 1949, this name wasn’t used. When Scott Redhead studied these species in the early 1980s, he synonymized T. ponderosum with the older species name magnivelaris, and transferred it into Tricholoma, which gave us the name most often used today: Tricholoma magnivelare.
But… Recent genetic work has shown that the western North American species is different from the eastern species. So it gets more complicated… We find out that Murrill described Armillaria arenicola from Newport, Oregon in 1912. At that time it was customary to call all white-spored mushrooms with attached gills and partial veil Armillaria). He also described a Tricholoma as T. arenicola at the same time. This only mattered because when Singer looked at Armillaria arenicola in 1942, he recognized that it belonged in Tricholoma, but had to give it a new species name, because the name T. arenicola was already in use for a different fungus. So he named it Tricholoma murrillianum, and now we have Murrill’s Matsutake.
However, these is a proposal in the works to preserve the name T. magnivelare for the western North American species, and T. matsutake for the eastern NA/Eurasian species."
A strong case can be made for conserving the name T. magnivelare for the western Matsutake. T. magnivelare in eastern NA doesn’t have the same ‘fame’ as it does in the west,and it doesn’t have much of a history of use there, considering that it was/still is called Armillaria ponderosa by many. Likewise, the name T. matsutake is very well known and researched in Asia, and to change that name to T. magnivelare would confuse matters more.
We had the case a few years ago with the popular and well known name Psilocybe being conserved for the “Blue Stainers”, which based on nomenclature technicalities, should have become Weraroa; and what now is Deconica, would have stayed Psilocybe.
There are a number of other well known names that should be conserved, Boletus bicolor and Suillus pictus are two northeastern species that come to mind. And for christ sake, nobody wants to call our Laccaria, Hydnangium amethysteo-occidentalis…