( CNN ) -- A flowering California shrub thought to be extinct in the wild for almost seven decades was added to the federal endangered species list Wednesday after a sharp-eyed biologist spotted the plant on a highway median while driving off the Golden Gate Bridge . The last known Franciscan manzanita ( Arctostaphylos franciscana ) was discovered in 2009 during a highway construction project , and after genetic tests confirmed the species , the state spent $ 109,000 on a crane to move the plant and its 12.5-ton root ball to another site so the $ 1 billion project could continue , federal and state officials said . The low-growing coastal shrub was relocated to another area in the Presidio of San Francisco , a 1,491-acre national park next to the Golden Gate Bridge , federal officials said . The evergreen is estimated to be more than 50 years old and was growing a few feet from traffic along the Doyle Drive roadway , also designated as U.S. Highway 101 , which connects the bridge and San Francisco , officials said . Cry endangered wolf ? Not in Wyoming . The plant lay hidden under eucalyptus and other trees , officials said . When the trees were cleared , the manzanita became visible for the first time in decades and was spotted by biologist Daniel Gluesenkamp , director of habitat restoration for Audubon Canyon Ranch , who was driving home from speaking at a climate change conference , according to federal officials and the Wild Equity Institute . Gluesenkamp noticed the unusual plant while driving 40 mph in heavy traffic , and he confirmed his suspicions about the plant 's identity when he returned to the site a few days later , the institute said . The manzanita was last seen in the wild in 1947 when a botanist stood in front of earth-moving equipment and saved what was then believed to be the last known wild specimen from a construction site , the institute said . The botanist sent the plant to a botanical garden . The manzanita found in 2009 had grown to a healthy size : Its roots stretched 20 feet wide and sank 18 inches into the soil , officials said . The plant 's bright green leaves are smooth , flat and wider toward the tips . The shrub likes open bedrock outcrops and reaches 3 feet in height , displaying pinkish flowers from January to April . It reproduces from seed after a fire or other disturbance , and the seeds are eaten and dispersed by raccoons , coyotes , foxes , deer , rodents , quail and turkey , the wildlife service said . The agency is now proposing about 318 acres of federal and state parkland in San Francisco and the surrounding county be designated as critical habitat for the shrub , said U.S . Fish and Wildlife Service spokeswoman Sarah Swenty . Clues to saving Tasmanian Devil from extinction . The plant is known only to exist on the San Francisco peninsula area and prefers serpentine soil , a low-nutrient area that allows it to out-compete non-native plants , officials said . `` Genetic diversity in plants is really important , as in animals as well , '' Swenty said . `` When you lose a link in the chain , there are unknown consequences that you ca n't see . `` This plant has been used to prevent erosion on our hillsides in the San Francisco area , so it is certainly of benefit to people as well as plants , '' Swenty added . The Wild Equity Institute said protecting the long-lost plant under the Endangered Species Act closes `` one of our coldest conservation cases . '' The institute petitioned the federal government to put the plant -- `` a subtly charming flowering shrub , '' the group says -- on the endangered species list , the organization said . The Center for Biological Diversity and the California Native Plant Society co-petitioned for the protections , the institute said . Invasive species : Eat them before they eat everything .
The Franciscan manzanita is a rare plant found only on San Francisco peninsula . It has been believed extinct since 1947 . A highway construction project removes trees covering the plant ; passing biologist notices it . The plant and its large root ball are relocated ; feds the shrub on endangered list .