The system provides clear definitions and codes for recording plant distributions at four scales or levels, from "botanical continents" down to parts of large countries.
Current users of the system include the International Union for Conservation of Nature (IUCN), the Germplasm Resources Information Network (GRIN), and Plants of the World Online (POWO).
[2] The starting point was the "need for an agreed system of geographical units at approximately 'country' level and upwards for use in recording plant distributions".
Thus the scheme follows Flora Europaea[5] in placing the eastern Aegean islands (such as Lesbos, Samos and Rhodes) in the West Asia region,[6] rather than in Europe where they belong politically as part of Greece.
The WGSRPD defines nine botanical continents (Level 1), each assigned a single digit code from 1 (Europe) to 9 (Antarctica).
[3] The botanical continent of Europe is defined broadly in line with Flora Europaea[5] and with the traditional geographical definition.
The eastern boundary places Crimea and European Russia in Europe, with the border defined by the administrative units.
It excludes the Sinai Peninsula, politically a part of Egypt, which is placed in region 34 Western Asia.
To the south-east, the Indian Subcontinent and the rest of Asia from region 41 Indo-China southwards are placed in Asia-Tropical.
[14] The botanical continent of Australasia, as defined by the WGSRPD, consists only of Australia and New Zealand, plus outlying islands.
The WGSRPD groups most islands with a nearby continental landmass, usually the closest but may also make a decision influenced by the floristic similarity (hence the placement of the Azores with Africa and not Europe).
The exception is the islands of the central part of the Pacific Ocean, which are placed in a separate botanical continent.
43 Papuasia Organizations and works using the scheme include the International Union for Conservation of Nature (IUCN),[27] the Germplasm Resources Information Network (GRIN), and the World Checklist of Vascular Plants, which supports Plants of the World Online, published by Kew.