It is native to warm temperate and tropical regions of the Americas, and has been introduced to Europe, North and sub-Saharan Africa, China, Japan, New Zealand, Australia, the Caribbean and Hawaii.

[4] It is a floating aquatic fern, with very fast growth, capable of spreading over lake surfaces to give complete coverage of the water in only a few months.

Each individual plant is 1–2 cm across, green tinged pink, orange or red at the edges, branching freely, and breaking into smaller sections as it grows.

[8][7] The only sure method of distinguishing this species from Azolla cristata (long incorrectly known as A. caroliniana) is to examine the trichomes on the upper surfaces of the leaves.

It was introduced into Asia from East Germany in 1977 as an alternative to the cold susceptible native strain of A. pinnata, used as a green manure in the rice industry.