<i>Consolea corallicola</i> commonly known as the "Semaphore Prickly-pear Cactus", is only found on a few keys in southern Florida and may be the rarest plant in the United States
National Park Service
2012-12-01 12:39:50
Natiional Park Service website <a rel="nofollow" class="external autonumber" href="http://www.nps.gov/bisc/naturescience/cacti.htm">[1]</a>