More images of Azolla
Genus of around 7 prolific, floating, aquatic fern species also known by the names duckweed fern, fairy moss, water fern and mosquito fern for their appearance and aquatic habit. They do not resemble traditional terrestrial ferns, they are reduced and adapted to aquatic habitats, appearing more like duckweed or a moss. Species are typically deciduous and perennial, grown for their decorative foliage and as algal control in ponds. However they can spread invasively, doubling in biomass every 3 days in optimal conditions, so must be controlled carefully.
Other uses of Azolla
Grown for the foliage and to control algae by reducing light beneath water.