Why is Joel Roberts Poinsett important?

That he is the first person known to have introduced poinsettias (Euphorbia pulcherrima) into the United States of America is one reason why botanist, physician and statesman Joel Roberts Poinsett (March 2, 1774 - December 12, 1851) is important.

Specifically, the plant is native to southwestern Mexico and Central America. But until the time of Poinsett the plant remained known only to the indigenous inhabitants and Spanish-speaking settlers of Mexico. While serving as first U.S. Minister to Mexico during the years 1823-1830, Poinsett discovered the plant growing in the wild. As a trained botanist, he immediately recognized the plant's scientific importance. As of 1828, he therefore began sending specimens back to his own greenhouses in South Carolina as well as to select botanist friends.