Insanity Prawn Boy's picture

Thongweed button (Himanthalia elongata)

Observed: 14th November 2012 By: Insanity Prawn BoyInsanity Prawn Boy’s reputation in Plants

Plant, I thought a seaweed, now identified as Thongweed (see identifications below) on Filey Brigg (a wave cut promontory on the North Yorkshire coast), November 2012.

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markwilson's picture


From the MarLIN site

A common brown seaweed, which has a two stage morphology. Small button-like thalli are first produced, from which long strap-like reproductive fronds (receptacles) are formed in autumn. The strap-like reproductive fronds grow quickly between February and May, reaching a length of up to 2 m. The plant releases gametes from June until the winter when it starts to decay. Plants commonly live for 2-3 years and reproduce once before dying.

This is a plant of shores exposed to moderate wave action - I think the smaller seaweed around it is Pepper dulse - Osmundea pinnatifida (was Laurencia when I was a lad !)

Insanity Prawn Boy's picture


Thanks for the identification. The location it was in is exposed to considerably more than moderate wave action, perhaps why I only saw this one! The three stalks will be the beginning of the fronds, then.

chrisbrooks's picture


Yes you are correct.