October 13, 1998 – The U.S. Fish and Wildlife Service listed the thread-leaved brodiaea as threatened under the Endangered Species Act.
November 15, 2001 – The Center and the California Native Plant society filed suit against the Service for of its failure to designate critical habitat for eight plant species, including the thread-leaved brodiaea.
July 1, 2002 – The U.S. District Court for the Southern District of California ordered the Service to produce a determination on granting critical habitat for the thread-leaved brodiaea, and to publish a final rule on critical habitat by November 30, 2005.
December 8, 2004 – The Service proposed allocating 4,690 acres of critical habitat for the thread-leaved brodiaea.
December 13, 2005 – The Service published a final rule designating just 597 acres of critical habitat for the plant.
August 28, 2007 – The Center filed a notice of intent to sue the Bush administration for wrongful Endangered Species Act decisions affecting 55 species, including the designation of insufficient critical habitat for the thread-leaved brodiaea.
December 19, 2007 – The Center filed suit against the Bush administration for its failure to protect the thread-leaved brodiaea through proper designation of critical habitat, as well as failing to sufficiently protect 12 other species.
June 18, 2008 – The Fish and Wildlife Service agreed to consider granting the thread-leaved brodiaea more habitat protections. A deadline for a new proposed critical habitat designation was set for 2009, with a final decision slated for the next year.
December 8, 2009 – The Service proposed to protect 3, 786 acres for the plant — a great improvement over its 2005 designation but still a failure to protect 49 percent of existing plants.
February 8, 2011 – The Service finalized a new critical habitat designation for the brodiaea of 2,947 acres.