Azolla filiculoides

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Azolla filiculoides

Scientific classification
Kingdom: Plantae
Division: Pteridophyta
Class: Pteridopsida
Order: Salviniales
Family: Azollaceae
Genus: Azolla
Species: A. filiculoides
Binomial name
Azolla filiculoides
Lam.

Azolla filiculoides (Water Fern) is a species of Azolla, native to warm temperate and tropical regions of the Americas.

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. It is not tolerant of cold temperatures, and in temperate regions it largely dies back in winter, surviving by means of submerged buds. Like other species of Azolla, it can fix nitrogen from the air.

Fossil records from as recent as the last interglacials are known from several locations in Europe (Hyde et al. 1978).

[edit] Cultivation

The species has been introduced to many regions of the Old World, grown for its nitrogen-fixing ability which can be utilized to enhance the growth rate of crops grown in water like rice, or by removal from lakes for use as green manure. It has become naturalized, sometimes also an invasive species, in several regions, including western Europe, southern Africa, tropical Asia, Australia, and New Zealand.

[edit] References