As you stated Alocasia Amazonica is a hybrid while Alocasia sanderiana is a scientifically described species. Without examining the scientific characteristics it is very difficult to tell them apart. according to Bill Rotolante of Silver Krome Gardens in Homestead, FL Alocasia Amazonica is either a hybrid of Alocasia watsoniana x Alocasia sanderiana or a cross between Alocasia watsoniana x Alocasia nobilis. If you check the scientific sources you'll find that Alocasia watsoniana is a synonym and is now correctly Alocasia longiloba. You can find many of the characteristics of any of these species by logging onto TROPICOS which is a service of the Missouri Botanical Garden in St. Louis. If you look up a species' name then click on "Specimens" you will find a list of collections which will tell you where the species originates. Go down the list and look to the extreme right side and click on the accession numbers. Some, but not all, will list the field notes of a variety of botanists and you can frequently find detailed information about the stem, petioles, cataphylls, blades and inflorescences. If you compare those characteristics to your plant you may find similarities or differences. Botanists Pete Boyce in Malaysia and Alistair Hay in Australia are the two best sources for accurate information. If you'll send me a personal email I'll gladly give you their email addresses. The method of growing any is the same, just be sure and use a very porous soil. You can find my address at the bottom of the homepage on the ExoticRainforest website or send a note through GardenWeb. Steve

A.sanderiana has much larger lobes on the leaf .

Narrow as the Sword.

Alocasia sanderiana can grow upto 4 feet tall while amazonica can only grow 2 feet