Plant Diversity by Ecological Region

According to the World Wildlife Fund, the following ecological regions have the highest number of plant species:

Ecological region	Countries
Atlantic moist forest complex	Argentina, Brazil, Paraguay
Northern Andean moist forest	Colombia, Ecuador, Venezuela
Choco-Darien moist forest	Colombia, Ecuador, Panama
Napo moist forest of Amazon & Orinoco basins	Colombia, Ecuador, Peru
Sumatra, Mentawai & Nicobar Islands moist forest	Indonesia, India
Fynbos	South Africa
Kwongan heathland	Australia

The World Wildlife Fund rates the following ecological regions as being second highest in plant species globally:

Ecological region	Countries
Central and southern Andean yunga	Bolivia, Colombia, Ecuador, Peru, Venezuela
Peninsular Malaysia forests	Malaysia
New Guinea lowland moist forest	Indonesia, Papua New Guinea
Southern Mexican dry forest	Mexico
Madagascar dry forest	Madagascar
Mexican pine-oak forest	Mexico, Guatemala
Appalachian Mountains & mixed mesophytic forest	United States
Southeastern coniferous forest/sand pine scrub & pine rockland (highest herbaceous richness anywhere)	United States
Caucasus & northeast Anatolia temperate forest	Georgia, Azerbaijan, Turkey
Temperate forest of Sichuan & southern Yunnan	China
North American mixed- & tallgrass prairie	United States
Sonoran, Baja & Sinaloan cactus scrub & xeric shrubland	Mexico & United States
Chihuahuan, Pueblan cactus scrub, northern & central Mexican cactus scrub & xeric shrubland	Mexico & United States

According to the World Wildlife Fund, the following is the most species-rich boreal forest region:

Northwest Canadian boreal forest

According to the World Wildlife Fund, the following are the most species-rich Arctic tundra regions:

Ecological region	Countries
Alaskan North Slope coastal tundra	United States & Canada
Chukotsky coastal tundra	Russia

Brooklyn Botanic Garden