Sea Knotgrass
Sea Knotgrass on a sandy beach in
West Cornwall
Groups of flowers on flower spike
4 tepals, yellow stamens
Veined, silvery flower sheaths
Leaves with recurved margins
Habit - sprawling over small rocks
Polygonum maritimum
Polygonaceae
July to September
It is found patchily on the coasts of the South and the far
Southwest,
See the BSBI distribution map for Sea Knotgrass
It grows on sandy, shingle and shell seashores above
the highest tide line.
Sea Knotgrass is a native, prostrate, greyish, perennial
herb, growing up to 40cm.
Flowers (1-4 together) are at the end of the leafy spike.
Tepals (5) are pink, greenish or white.
Leaves are up to 15mm, slightly leathery and with down
turned margins
They have long (up to 1cm) sheaths, which are silvery
with 8-12 branched veins.
Fruits are brown nuts, which protrude above the dead
flowers (not shown here. See similar on Ray's Knotgrass
- June).
Stems are stout and woody at the base.
Previous page: Sea-heath
Next page: Sea Mayweed
Sea Knotgrass on a sandy beach in
West Cornwall
Groups of flowers on flower spike
4 tepals, yellow stamens
Veined, silvery flower sheaths
Leaves with recurved margins
Habit - sprawling over small rocks
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