Madrean Region
（重定向自Madrean）
![Yucca brevifolia in Joshua Tree National Park](/Images/godic/202501/25/Jtree3841.jpg")
![Eschscholzia californica in the Antelope Valley](/Images/godic/202501/25/California_Poppies13841.jpg")
![Fouquieria splendens in Tucson in winter](/Images/godic/202501/25/Ocotillo-6003842.jpg")
![Young Larrea tridentata](/Images/godic/202501/25/Creosote_Larrea_tridentata3842.JPG")
The Madrean Region (named after the Sierra Madre Occidental) is a floristic region within the Holarctic Kingdom in North America, as delineated by Armen Takhtajan and Robert F. Thorne. It occupies arid or semiarid areas in the southwestern United States and northwestern Mexico and is bordered by the Rocky Mountain Region and North American Atlantic Region of the Holarctic Kingdom in the north and in the east, as well as by the Caribbean Region of the Neotropical Kingdom in the south.