The Amazon strain was originally sold as “P.E.S. Amazonia.” P.E.S. stands for Pacifica Exotica Spora — the company that first started selling the spores for this strain.
It was trendy for a while to name a newly discovered strain after the company that “discovered” them, but this isn’t a common practice anymore. Now there are plenty of other vendors that sell the Amazon strain simply as “Amazon” or “Amazonian Cubensis”.
Amazon is a very large mushroom strain and grows surprisingly quickly for its size. Part of the reason they can grow so large so quickly is the fact that this strain has hollow stems. They shrink quite a bit when you dry them out.