Peru

Its English name says Peru; its Latin name points at a town in Mexico.

The plant reached European gardens from Spanish America in the sixteenth century and was sold as a marvel out of Peru, the name Spanish ships attached to a great deal of the continent. Its species name jalapa refers to Xalapa in Mexico, and botanists still disagree about where the wild ancestor actually grew.

The powder keeps you marching and the adjective says where the coca grew.

Peru is one of the three Andean countries that between them grow almost all the world's coca, and the phrase is in print by 1979. The better known variant names Bolivia, largely because Jay McInerney used Bolivian marching powder throughout Bright Lights, Big City in 1984. Cocaine slang leans heavily on the name of the source country.