COLUMBUS, Ohio (AP) -- The state flag of Ohio is featured on a new postage stamp.

The U.S. Postal Service says the flag appears with a butterfly and milkweed plants along a riverbank on the stamp being issued Thursday as part of the post office's ongoing "Flags of Our Nation" series.

States have joined the series in alphabetical order. Flag stamps for Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota and Tennessee also are being introduced on Thursday.

The new stamps are "Forever stamps," meaning that they can always be used on a first-class letter even if postage rates go up.

Postal Service Chief Operating Officer Megan Brennan will dedicate the stamps during a ceremony in Columbus, at the 2011 American Philatelic (fil-uh-TEHL'-ik) Society Stamp Show.