Alocasia x Amazonica is a bogus use of that name form according to botanist Alistair Hay in Australia. Alistair is one of the two top Alocasia botanists in the world. If anyone wanted to use this type of name Alocasia x mortefontanensis would be the only one of the two that meets the standard for this usage since it was scientifically published while Alocasia x Amazonica was never officially published in science.
You will find Alocasia x Amazonica on a number of websites including a major botanical garden in Belgium but that name simply is not qualified. It appears the curator, Madam Billiet, elected to post the name on their website but I am personally aware of several botanists as well as a botanical garden in France that have advised them against the use. I have corresponded with their greenhouse keeper on this subject but the last I heard they did not intend to make any changes to their site.
Alocasia x Amazonica was also used until just a few months ago on the USDA site as well as a couple of University horticulture websites until I sent them copies of Alistair's email. Within days they had removed the use.
I suspect Rachel has been reading my site! If any of you would like to read the entire story just go to www.ExoticRainforest.com and click on the Plants in the Collection link in the gold box.