Don’t look now, but the holidays are fast approaching.

One sign is the issuing of seasonal stamps by the United States Postal Service. This year’s classic is a rendering of America’s favorite holiday flower, the poinsettia.

Available now in sheets of 20 stamps, customers may purchase the stamps at usps.com/stamps, at 800-STAMP24 (800-782-6724) or at Post Offices nationwide and on eBay at ebay.com/stamps. The Poinsettia stamps are also available at ATMs in booklets of 18 stamps.

“The image of the Poinsettia has proven to be so timeless that the Postal Service has featured it on two previous holiday stamps, one in 1964 and one in 1985,” said U.S. Postal Service Stamp Services Director Susan McGowan.

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.

Artist William Low of Huntington, New York, working under the direction of Ethel Kessler of Bethesda, Maryland, created the digital painting in Photoshop. Using a cordless pen or stylus, he “painted” his brushstrokes on a pressure sensitive screen, adding dabs of color and weaving layers of texture into the painting.

A potted poinsettia served as Low’s model. In order to keep the image fresh after the live plant passed its prime, he photographed the flower at its peak, capturing details in close-ups and preserving the perfect light that accentuated the poinsettia’s vivid color.

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.

(Photo courtesy of the U.S. Postal Service)