A block of four commemorative stamps featuring desert plants that grow in the American West was issued December 11, 1981, at Tucson, Arizona. All of the plants depicted are found in the state of Arizona.
Three of the plants — the Barrel Cactus, the Beavertail Cactus, and the Saguaro — are in the cactus family. The fourth plant featured, the Agave, is assigned to the amaryllis family by most botanists.
The stamps were all designed and modeled by Frank J. Waslick of the Bureau of Printing and Engraving. The stamps were printed in the offset/intaglio process, with forty stamps per pane.
Postal Bulletin (November 19, 1981).