Jul 15
#3832 - Azolla rubra - Red Azolla
AKA returetu, roturotu, kārearea and kārerarera, and Pacific azolla.
A floating aquatic fern native to Australia and New Zealand, and possibly as far afield as Japan. It rapidly multiplies to form mats on still or slow-moving water, and gets redder as it ages.
Azolla enjoys an obligate symbiosis with the cyanobacterium Anabaena azollae, which fixes atmospheric nitrogen for the plant and can no longer survive away from the fern.
During the Eocene, when the Arctic Ocean was mostly freshwater for roughly 800,000 years, Azolla grew in such gigantic quantities that it sucked enough carbon dioxide out of the air to cause global cooling.
Duntroon, Aotearoa New Zealand.
