Peaceful Patterns of Pelvetiopsis and Fucus on a High Reef

A surf swept reef is a boisterous place. Crashing waves elicit profound vigilance and the footing is treacherous. A spill will earn you a painful barnacle inflicted wound. To let your mind wander to the artistic is to risk a tumble or a soaking.

Seascape with waves hitting the reef
Exposed high reef | in the foreground, a carpet of Pelvetiopsis limitata

Still, it’s possible to find peace in the artful patterns of the invertebrates and algae. I’m going to go ahead and feature the dichotomous branching patterns of two related mid- to high intertidal brown algae. Below, Pelvetiopsis limitata, with its y-shaped branches, expanded at the tips where eggs and sperm are produced. Roaring surf will be close at hand when you’re on the Pelvetiopsis beds.


Just landward, in protected troughs, Fucus distichus forms lavish beds. When you come upon such a bed, secure yourself on a comfortable perch amid the lush growth. Letting yourself go face-to-face with the Fucus is recommended.

A sheltered trough with a lush covering of Fucus

Fucus branches a lot like Pelvetiopsis. They’re both in the family Fucaceae- all its members branch like this. You may notice other similarities, like expanded branch tips. And you might notice the branches of Fucus have a midrib, while those of Pelvetiopsis don’t. If you are lucky enough to get an intimate view of Fucus, pay attention. It’s morphologically plastic, so, depending on environmental conditions, the next bed or clump you encounter might give you a new look.


I chose to feature this pair of phycological patterns because they originate from close relatives and they live on the same rocks and reefs. I took the more intimate photos of Pelvetiopsis and Fucus on the same reef about four minutes apart, but in different habitats. They’re similar, but different enough to be interesting.

Pelvetiopsis and Fucus are two among many Pacific brown algae. To see my take on Pelvetiopsis and Fucus, and a bunch of other browns, take a look at Brown Algae, Ochrophyta.

This isn’t the first time I’ve written about intertidal patterns. In 2016 I wrote Life Imitates Art in the Intertidal and The Abstract Intertidal.