If you explore a rocky beach of the Pacific Northwest,
You might meet a large brown seaweed, whose name you could only guess.
Finding them is easy, but to ID, you might need some help,
So next time you meet one, remember this poem about kelp.
Before we dive into our identification quest,
Let’s cover some terminology, so we can understand the rest:
A blade is like a leaf, a stipe is like a stalk,
A midrib gives blades structure, a holdfast sticks stipe to rock.
So, first things first, can it grow 50 metres tall?
If so, then it’s Macrocystis pyrifera, the largest kelp of them all.
Together, they form forests, home to fish, sea otters, and more,
But you’ll most likely see them when they are swept ashore.
But there is another kelp that can reach a similar height:
Nereocystis luetkeana, which boasts a 36 metre-long stipe.
Smooth, narrow blades extend from its bulbous air bladder
Which holds carbon monoxide! But, eh, that doesn’t really matter…
Most other kelps are much smaller, but just as cool
Such as Laminaria ephemera, often found in tide pools.
Much like Laminaria yezoensis, it has a disc-shaped holdfast
But it’s narrower and shorter-lived, so there’s still some contrast.
The base of some kelps might give their identity away,
As only some have sporophylls, special reproductive blades.
If you should spot any, count the rows you see,
It may be Alaria marginata, which has two rows of these.
The many shapes of Costaria costata may initially perplex
As its blade’s width varies with the wave action’s effects.
But this kelp has five midribs, as if one weren’t enough,
So identifying this one shouldn’t be too tough.
Like other kelps, this one likes substrates rocky, not sandy;
Its palm-tree-like shape makes its morphology most handy.
Postelsia palmaeformis, or sea palm for short,
It’s easy to ID, as the only kelp of its sort.
Now, there’s so many kelps, I could go on forever,
But I only have minutes for what would be a lifelong endeavour.
So I’ll stop here, but hopefully by this poem’s end,
You’ll be able to name some of our photosynthetic friends.
Visuals: https://docs.google.com/presentation/d/1e14rjC5q4wH-_tQXGMRgFYLEs3mnncM-ZYk8hdtd5rY/edit?usp=sharing