The stamp art depicts the rich red and vibrant green leaves surrounding the flower — the cluster of small, rather modest cup-shaped structures in the center. The red “petals” that we think of as the flower are actually modified leaves called bracts.

In addition to red, America’s favorite poinsettia color, the modern plants are bred in many hues:  pink, apricot, yellow, cream, and white, among others, with some unusual varieties that blend several colors in a speckled or marbled pattern.

Native to Mexico, the poinsettia — its botanical name is Euphorbia pulcherrima — is a small tropical tree that can reach heights of more than 10 feet in the wild. The Aztecs revered the poinsettia, which they called cuetlaxochitl, as a symbol of purity. They used the bracts to make a reddish-purple dye for textiles and cosmetics and created a medicine from the plant’s milky sap that counteracted fever.