Stinky Pear Invasion

This photo made available by the U.S. Department of Agriculture National Agricultural Library, Special Collections, shows an unidentified man holding a spur of a large Callery pear tree next to a pine tree during an expedition to collect plants in China for the USDA, on March 31, 1917. The location, described as "near Nan chang yen, Hupeh, China," may have been in Nanzhang county in Hubei. "Very few trees find pine trees congenial mates, but this remarkable Calleryana pear occurs at times quite plentiful in open pine forests, on sterile mountain slopes," USDA plant explorer Frank N. Meyer wrote to his supervisor. Invasive varieties of Callery pear have been reported in at least 33 U.S. states. (Courtesy of USDA via AP)