Category
page 1Floristic provinces
Sonoran Desert
desert in northwestern Mexico and the southwestern United States
Macaronesia
thumb|240px|Macaronesia
Great Basin
large depression in western United States

phytochorion
In phytogeography, a phytochorion is a geographic area with a relatively uniform composition of plant species. Adjacent phytochoria do not usually have a sharp boundary, but rather a soft one, a transitional area in which many species from both regions overlap, called a vegetation tension zone, or ecotone.