Most biodiverse island (flora)
New Guinea
13,634 total number
Not Applicable ()

A paper published online by the journal Nature on 5 August 2020 revealed that New Guinea in the south-west Pacific Ocean is home to 13,634 species of vascular plant – making it the island with the richest flora. The diverse plant life of the world’s second-largest island comprised 1,742 genera and 264 families, and, what’s more, 68% of the species are endemic. By far the largest group of plants that were documented were orchids, which accounted for one-fifth of the total species – and of those, the most diverse genus is Bulbophyllum with 658 species (599 of which are found nowhere else on Earth).

This puts New Guinea ahead of Madagascar by 19% (with 11,488 documented vascular plant species) and Borneo by 22% (with 11,164 plant species).

Scientists put this unparalleled diversity down to the fact that New Guinea straddles several eco-zones sitting in the junction between South East Asia, Australia and the Pacific. It also boasts extremely varied habitats, from mangroves to lowland rainforest and alpine grassland, enabling many different plants to thrive.

New Guinea is divided politically into Papua New Guinea (east) and Indonesian New Guinea (west); the former has more plant species recorded with 10,973 species (44% more than the Indonesian territory), but this may in part be due to the far greater number of scientific collections made in Papua New Guinea.

The comprehensive study was a collaboration between many universities and botanical institutions around the world, led by Royal Botanic Gardens, Kew (UK).