Greater Duckweed - Spirodela polyrhiza
This is an aquatic plant, usually growing in dense colonies, forming a mat on the water surface. Each plant is a smooth, round, flat shiny green disc on top and often purplish underneath. It may measure 4 to 10 mm across and produces several minute roots (at least two, unlike Common Duckweed).
Many roots, large fronds, reddish underside and turns red in autumn, multiple veins
The County Recorder has asked for a specimen of this plant to be retained for verification
Mainly found in still water such as ponds.
Spring and summer, dying back in the autumn.
British records are mainly concentrated in central and southern England.
Scarce in Leicestershire and Rutland. In the 1979 Flora survey of Leicestershire it was found in 7 of the 617 tetrads.
It is now listed in the VC55 Rare Plant Register (Jeeves 2011)
Leicestershire & Rutland Map
Enter a town or village to see local records
Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015