Zingiber officinale
Ginger root is probably the most widely used herb for holiday beers. The rhizome grows in the tropics and was brought by Spanish conquistadors to the New World via Jamaica.

Zingiber officinale The pungent taste of ginger is due to nonvolatile phenylpropanoid-derived components, particularly gingerols & shogaols, which form from gingerols when ginger is dried or cooked. Mature ginger roots are fibrous & nearly dry. Powdered dry ginger root is typically used as a flavoring for recipes such as gingerbread, cookies, crackers & cake, ginger ale & ginger beer.