What is "phytochorion"

n. A geographic area with a relatively uniform composition of plant species.

A phytochorion, in phytogeography, 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. The region of overlap is called a vegetation tension zone.

In some schemes, areas of phytochoria are classified hierarchically, e.g., in Floral (or Floristic, Phytogeographic) Kingdoms, Regions and Provinces, sometimes including the categories Empire and Domain, while others prefer not to rank areas, referring to them simply as "regions" or "phytochoria".

The systems used to classify vegetation can be divided in two major groups: those that use physiognomic-environmental parameters and characteristics and those that are based on floristic relationships. Phytochoria are defined by their plant taxonomic composition, while other schemes of regionalization (e.g., phytophysiognomies, formations, biomes) may variably take in account, according to the author, the apparent characteristics of a community (the dominant life-form), environment characteristics, the fauna associated, anthropic factors or political- conservationist issues.