Botanical Name: Zanthoxylum piperitum, Z. simulans, Z. bungeianum, and others
Common Name: Sichuan Pepper, Flower Pepper
Origin: Native to all of East Asia; can be found in the Himalayas as well.
The most common name for this plant and its spice is derived from its regional spread and importance: Much of it is being grown in the Chinese province of Sichuan, and that province is also the fondest of huajiao, as the Chinese name labels it.
As it so often goes with rather new spices (although, it also does with black pepper and its varieties), only Sichuan pepper as a generic spice has been gaining greater awareness, but the differences (or that there even are differences) between types and origins is little understood.
In fact, though, at least some of the difference may even come down to their being entirely different species of plant…