Below you’ll see a few examples of common intertidal green algae from exposed surf-swept shores of the northern Oregon coast. These are ones you are likely to encounter on the rocks and in and around tide pools. You’ll also see some of them as drift on the beaches. Most of these are common and easy to identify with the readily available field guides (see References, below). I’m just trying to provide some alternative looks and a few natural history notes if I can think of something that hasn’t already been said. There are some common greens that provide identification challenges. I’ll show the the tough ones too, in hopes somebody will come along and help me out with proper IDs, or even guesses.

The organization more or less follows Kozloff (1993) and Lamb and Hanby (2005), showing species in the order they might be encountered in the field, from highest to lowest in the intertidal. Common names are usually some combination of those in Lamb and Hanby (2005) and Mondragon and Mondragon (2010). I lean on WoRMS for scientific names, and Algaebase when I want to dig deeper. I learn a ton by browsing the pages of Kozloff (1993). All photos are from northern Oregon unless otherwise noted in the caption.

Ulva intestinalis Everybody says Ulva intestinalis ubiquitous at splash zone and high intertidal seeps.


CladophoraSea moss is characteristic of the upper midlittoral, found with mussels, haystack barnacles, Fucus, and Endocladia.


Urospora penicilliformis – You can’t really argue with the common name green hair. This ID is tentative, but it’s a good match with the common name.


Ulva – Ulva is common on the exposed coast but really comes into its own in protected sites. Ulva was featured in Sea Lettuce, Ulva.


This Ulva looks a a lot like the one Kozloff calls U. taeniata.


Spongy cushion, Codium setchellii Codium setchellii, a resident of the low intertidal, appeared in Spongy Cushion, Codium setchellii



Harbo, R. M. 2011. Whelks to Whales: Coastal Marine Life of the Pacific Northwest. 2nd ed. Harbour Publishing Co.

Kozloff, E. N. 1993. Seashore Life of the Northern Pacific Coast. 3rd ed. University of Washington Press.

Lamb, A. and B. P. Hanby. 2005. Marine Life of the Pacific Northwest. Harbour Publishing.

Mondragon, J., and J. Mondragon. 2010. Seaweeds of the Pacific Coast. Shoreline Press.

Sept. J. D. 2009. The Beachcomber’s Guide to Seashore Life in the Pacific Northwest. Revised ed. Harbour Publishing.

Web Resources

The green algae page on the Netarts Bay Today website is one of the best references you’ll find for the Pacific Northwest.

Biodiversity of the Central Coast has a great page on greens.

Seaweeds of Alaska is a standard reference for the Pacific northwest. It has a great green algae page.


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