Britton & Rose Micranthocereus Backeb. 异名:Austrocephalocereus Backeb., Siccobaccatus P.J.Braun & Esteves Pilosocereus Byles & G. D. Rowley – tree cactus
(原始内容存档于2018-11-14). Gossard, G. The Joshua Tree, a Controversial, Contradictory Desert Centurion. Yellow Rose Publications. 1992. Shafer, Sarah L.; Bartlein
Philip C.J. Donoghue. Paleontological Evidence to Date the Tree of Life (PDF). Dating the Tree of Life 31. 2007 [2008-03-05]. (原始内容 (PDF)存档于2016-03-03)
the United States Code) §§ 第3–304節) "The tree genus Quercus, commonly known as the oak tree, is the national tree."(美國法典第36编(英语:Title 36 of the United States