Grateloup's little-lobed weed

Grateloupia montagnei

This red seaweed grows as brownish-red crusts on small mobile stones and pebbles in shallow water.  Very rarely, it also grows on loose fragments of hard, coral-like maerl. 

The crusts are firmly stuck to the stone and on close inspection have small erect ‘warts’, randomly scattered over the surface.  These are the seaweed’s reproductive bodies, which have a range of functions within the seaweed’s complex life cycle. 

This extremely rare seaweed is very vulnerable to extinction as it occupies so few locations and the gravel on which it lives could be affected by aggregate extraction.


European distribution

This red seaweed was previously known only from a few dredged specimens, collected from the French coast, mostly in the last century.  It has now been recorded from western Scotland, south-west England, the Welsh coast and a small inlet of Kilkieran Bay, County Galway, Ireland.


Conservation status/need

  • Grateloup's Little-Lobed Weed FactThis is a UK BAP Priority Species (BAP species are now Species of Principal Importance/Priority Species).
  • Species of principal importance for the purpose of conservation of biodiversity under the Natural Environment and Rural Communities Act 2006


Further information

Marine Life Information Network

JNCC - UK BAP Priority Species and Habitats