Water Fern, Azolla filiculoides


Short description of Azolla filiculoides, Water Fern

Water fern forms floating rosettes up to a few centimetres diameter, composed of branched fronds with rows of imbricate leaves covered with dense papillae. It is initially green, becoming reddish late in the season. Globular spore-bearing structures sometimes develop below the fronds.

Description of Azolla filiculoides, Water Fern status in GB

Invasive in southern England and coastal Wales, scattered mainly in coastal areas further north and in eastern Ireland.

Habitat summary: Azolla filiculoides, Water Fern

Water fernis most frequent in ponds, lakes, canals, ditches and slow flowing rivers. It will also occur in seepages and in the backwaters of rivers and streams with faster flow but is rarely abundant in these habitats.

Overview table

Environment: Freshwater
Species status: Non-Native
Native range: Northern America, Southern America, Central America, Alaska
Functional type: Land plant
Status in England: Non-Native
Status in Scotland: Non-Native
Status in Wales: Non-Native
Location of first record: v.c.21 (Pinner)
Date of first record: 1883

Distribution map

GB Distribution from BSBI

Author's name:

R.V. Lansdown

Last updated:

November 27th 2015

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Thin strip of image show tree trunk and bark