Identifying seaweeds

William Morris's 'Seaweed' wallpaper. Possibly not an actual species.

At first, before being overwhelmed by the 600 or so species around the UK, you might want to look at the thirty on the Field Studies Council's Common Seaweeds Chart. We have some copies you can borrow, but the chart won't break the bank at £3 if you want one of your own. The drawings are very clear and the reverse has a simple key to steer you in the right direction.

You might also like this simple chart of common seaweeds from Coastwatch.

We also have copies of Collins' Sea Shore of Britain and Europe (with drawings) and Oxford's Photographic Guide to the Sea and Shore Life of Britain and North-West Europe. These have more species and more detailed descriptions of the species.

But I've just bought a copy of 'Seaweeds of Britain and Ireland' by Bunker, Brodie, Maggs and Bunker and am finding the photos and descriptions very useful. There are several copies that you can borrow. I've made a guide to the species we often find on the 1st year field trip, and this book has completely transformed my confidence in identifying seaweeds. It's laid out very helpfully and there are lots of photos. This is the one I'd recommend most I think!

Here is a link to Emma Wells's 'Field Guide to the British Seaweed', which has a wide range of species and also keys. It makes a lot more sense to me now I've become a bit more familiar with the species. I don't find it that easy to flick through on line, and the photos are in alphabetical order rather than being next to species that look similar (as in the Bunker book) - but if you are prepared to use the keys and need something digital, I think it's very good for pointing out the important features of the different species.

There are photos and detailed descriptions on The Seaweed Site which you might find useful - it's an Irish website but most species should be similar. It includes 'alien' species which might have arrived too recently to be in the older keys below. It's also full of general information about seaweeds which might come in handy for your monograph.

Seaweed identification isn't always easy because plants can vary hugely in appearance according to the degree of wave action where they grow, how much light they receive - or even how much they've been eaten. They may not even be the colour you expect. So you do need to progress from just looking at pictures - with the help of a key you can look closely at detailed features of the algae and (with luck) reach a more accurate identification. And of course, showing your use of a dichotomous key is part of the assessment.

To demonstrate your proficiency, you can turn to Hiscock's 'Field Key to the British Brown Seaweeds' - it's quite approachable and doesn't use too much technical language. You can download it here. It's only £6 to buy from the FSC if you want a book of your own, and we do have copies you can borrow.

Alternatively, there is her 'Field Guide to the British Red Seaweeds'.  This one's out of print, but we have borrowable copies, and there is one in the library. You can also download it from the FSC website.

We also have the standard book for chlorophyta, Brodie et al.'s 'Green Seaweeds of Britain and Ireland'.  This is a more serious tome, using more terminology and microscopic examination. You might want to try it though to confirm your green seaweed hunches.

CC image by Conscious

Names change over time as taxonomists refine their ideas - so it's a good idea to check you've got the current version by using the Natural History Museum's Dictionary of UK Species.

You could use your new seaweed taxonomy skills to contribute to the greater good - the Natural History Museum and the British Phycological Society want the public's records for monitoring a range of species. They want to investigate how distribution is changing over time and in the face of global warming.

View more seaweed-related posts.