an amateur’s guide to identifying seaweed for pressing
If you’re interested in foraging for seaweed, the first thing you need to know is how to identify it. There are many different types of seaweed, in this post we’ll give you a brief introduction to some of the most common types of seaweed we find in Cornwall and how to identify them. Please bear in mind that we are not scientists, so we do our best with the tools we have available (i.e. a few key books and the internet!).
Seaweed is in leaf all year round, although the shapes of the leaves or fronds changes through the seasons. Sheltered shores provide better foraging opportunities because the seaweed is more protected from the crashing waves. Seaweeds usually attach themselves to rocks or other layers of the seabed, so rocky shores are home to more seaweeds than muddy or sandy beaches.
Seaweed is divided into three groups which are distinguished by their pigmentation - brown, red and green. So, rather handily, the colour of the seaweed is the first clue to identification!
Brown seaweeds are easy to spot on the tideline, where they are washed up after storms and form rotting heaps of squelchiness. The brown seaweeds which we see most often in Cornwall are different types of Kelp, low tide in Falmouth reveals swathes of Oar Weed which is also aptly known as Tangle, it lays flatly strewn across the beach - other types of Kelp stay upright. The latin name for Oar Weed is Laminaria digitata, so look out for the fronds divided into ‘digits’ or fingers. Another favourite seaweed to spot is Furbellows which grows up to 2 metres tall. The base of the seaweed is a hollow lumpy holdfast with claw-like growths which grip on to rocks, the wavy ruffles at the base of the stipe look like the ruffles on an Elizabethan collar and give it its common name, they have a purpose though - they help to dissipate wave energy. Despite it’s availability, we haven’t managed to successfully press much Kelp because the texture is often too thick and fibrous.
A ruffle of Furbelows on the beach
Red seaweeds are more difficult to see amongst the brown kelps, but once you see them it’s hard not to notice them whenever you walk along the tideline. 97% of red seaweeds are found in the marine environment, they are incredibly diverse, with approximately 7000 species worldwide, because they evolved more than a billion years ago. We have foraged and pressed lots of different types of red seaweed, they can sometimes be difficult to identify - in which case it is perfectly acceptable to label the pressing Rodophyta or Red Algae. Red algae tend to press very well because they contain agar which sinks into the paper during the pressing process. The colours of pressed red seaweeds are often surprisingly bright, rich magentas and cerises give the pressings a blossom-like quality. Particular favourites include Sea Beech, Sea Oak and Beautiful Fan Weed.
Green seaweed is predominantly found in freshwater, with a few notable exceptions such as Sea Lettuce and Gut Weed. Microscopic examination is often required to identify green seaweeds accurately - we tend to stick to the more easily identifiable varieties for that reason! Sea Lettuce is such a striking green it’s hard to miss, we often forage small pieces to layer on to mixed pressings. We were lucky enough to find Green Tarantula Weed once - and only once, it’s resemblance to dandelions is really striking.
Hand pressed Green Tarantula Weed
We rely very heavily on Seaweeds of Britain and Ireland, published by Seasearch, to identify our pressings. It is a brilliant book which leads you down a filtering process so you can pinpoint the growth forms of the different seaweeds to help you identify them as best you can.