Salviniopsida Polypodiophyta Plantae Flora and Fauna

Order of small, floating ferns with just two genera. Azolla is a tiny fern that floats in the paddy fields of Southeast Asia and is of considerable economic importance. There are pouches in its floating leaves that house the cyanobacterium Anabaena azollae. These bacteria fix nitrogen from the air and provide the rice fields with a valuable source of fertility.