Some more algae species
You will have already come across some of these species on shore and found one to be a bit of a challenge since it can often be difficult to separate from another species and neither species always stick to the regular text book appearance.
You will see what they like in different situations and learn of their ecology to help with ID.
You will then be tested.
The species in focus are:
false irish moss/ lafwr piws (Mastocarpus stellatus)
sea oak or pod weed (Halidrys siliquosa)
cuvie/môr wiail hirgoes (Laminaria hyperborea)
sugar kelp/môr wiail crych (Laminaria saccharina)
Some more algae
false irish moss/ lafwr piws (Mastocarpus stellatus)
©North Wales Wildlife Trust
- looking very similar to Irish moss (see Level 1 description) this red algae looks messier and is often a browner-red colour
- a bushy-looking algae it, like Irish moss,
- branches equally into two
- one diagnostic feature to look for is the shallow channel on the back of the frond, often only apparent close to where the algae is attached, low down on the specimen
- reproductive outgrowths all along the frond at certain times of year are also diagnostic, as Irish moss doesn’t have these (this algae has also been called grape pip weed, due to these outgrowths).
sea oak or pod weed (Halidrys siliquosa)
©North Wales Wildlife Trust
- a brown algae with long, sturdy, thin, branching fronds
- also called pod weed it has air-filled, bladders which look like seed pods on trees
- yellow-brown in colour
- branches alternately with flattened fronds, looks zig-zaggy
- can grow up to 1 metre in length
is a perennial.
cuvie/môr wiail hirgoes (Laminaria hyperborea) 
©North Wales Wildlife Trust
- similar to oar weed, this kelp is large with a large, wide, usually wave-torn blade
- the stipe is a clear difference between this and other kelp species – cuvie has a rough stipe which is usually covered in other algae and sea mats
- grows up to 3 metres
- can also be seen at low tide, but it’s often lower than oar weed.
sugar kelp/môr wiail crych (Laminaria saccharina)
©North Wales Wildlife Trust
- a kelp with a single, long frond this can grows to 3-4 metres long
- yellow-brown in colour
- has a small holdfast in comparison to many other kelp species
- the stipe has no mid-rib and has a frilly appearance
- a climate change indicator species.
Alternative factoids
Algae can be fascinating if you delve into the fronds for a closer look. Here are some extra snippets, on which you won’t be tested.
Kelp is a fast-growing group of algae, which mostly lose their fronds and grow a new one each year in the UK
Tuning fork weed is said to have Luisitanian distribution (likes the S.W tip of UK, especially S.W. Ireland and Iberia in Spain, but not inbetween)
In sugar kelp seasonal growths can result in growth rings, which can be used to help age the individual
Both Irish moss species suffer from many stressors in their growing environment that they produce something called “reactive oxygen” as they metabolise, designed to help protect them, but which can actually affect their DNA is found in excess.
Giant kelp (a particular species – Macrocystis Pyrifera growing in the Southern hemisphere’s temperate seas) can grow on average around 30cm a day.
The next section is the quiz. Click to begin the quiz, the questions will appear below. If you get any one question wrong within each quiz page, the you will be marked as wrong for the whole page. Answers will appear one you’ve finished each question.
You will be tested on what you’ve learnt so far using the reading and video info (but not the additional red algae workshop). Don’t worry too much, as once you’ve been out on the shore, the ID features you’ve learnt about will make more sense and after a couple of visits you should feel more confident about your ID.
Good luck!