That is a very interesting chart! What is a bigaridia? Is that another name for a sour orange?
Citrus taxonomy and genetics are confusing and frequently get reshuffled (poncirus moves in and out of citrus roughly every 50 years, and the oceanian citrus and fortunella get this treatment, too). The Seville orange was once thought to be its own species (citrus bigaradia). It has since been moved into citrus x aurantium -- the sour (or bitter*) orange.
Bigarade is a French name, but it finds its way into English occasionally. Amusingly, in Hindi it means "spoiled."
* -- poncirus is also known as the bitter orange. One reason I prefer using sour/hardy as the phrasing instead.