http://www.candyblog.net/blog/item/classic_gums

Teaberry is a regional name for wintergreen (also known as Canada tea,
which may explain the name of Canada mints which are also wintergreen
flavored).

The D.L. Clark Company used to be a rather large & diverse candy
manufacturer in Pittsburgh, Pennsylvania which made both candy bars and
gums starting in 1886. At one point the company was making 150 different
kinds of confections. In 1921 the gum side of the business (which was
made in a separate factory anyway) was spun off into its own company:
Clark Brothers Chewing Gum Company (later shortened to Clark Gum
Company). They were best known for two flavors: Teaberry and Tendermint.

Though Tendermint is no longer produced, Teaberry is still available.