Most wood labeled as boxelder is an "Acer", that is, a member of the maple family and grows in the US and Canada. Some of the burls and grain patterns can be "exotic". (There is no established definition for exotic wood that I know of -- marketing term)
boxelder tends to be pretty soft and does well with plastics injected into the wood. It also dyes well.
Some of Bill's double dye box elder blanks are outstanding on a dark night, let alone on a bright day.