Below you’ll see examples of intertidal red algae from exposed surf-swept shores of the Oregon coast. You are likely to encounter these reds on the rocks or in and around tide pools, and you’ll see some of them as drift on the beaches. Some of these are easy to identify with field guides and online resources (see References, below- these are the resources I use), others are tricky. I apologize for any misidentifications you find. I try to get the IDs right, but I’m far from an expert. There’s nothing new here, just new looks at common reds, and a natural history note if I can think of something from my experience that hasn’t already been said. Since identification can be a challenge, I’ll show the tough ones too- the ones I can’t identify. Please drop me a line if you notice a misidentification or can help me solve a mystery red.
My organization more or less follows Lamb and Hanby (2005), showing species in the order they might be encountered on the shore, from highest to lowest in the intertidal. Common names are my choice. 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 mine, and all are from northern Oregon, unless otherwise noted in the caption.
Nori or Laver, Pyropia
I can only guess which species are represented below, so I won’t even try. You’ll see these as Porphyra in some of the guides. Druehl and Clarkston (2016) indicate most of the Porphyra we encounter in Oregon have been reassigned to Pyropia. Most of my experience is with the limp thalli, exposed by the receding tide. To the eye Pyropia, at least the one shown here, is iridescent. To the touch it has a rubbery quality. This one is common in the high intertidal, among the acorn barnacles. A heavy growth can obscure rocky details and make slippery footing.
Bald sea hair, Bangia
Just as the common name implies, on rounded high intertidal rocks, Bangia looks and behaves like thinning human hair. Bangia is featured in A Brief Account (with Video!) of the Bangia-Human Hair Resemblance.
Nail brush, Endocladia muricata
Also called sea moss, Endocladia is one of the common tufts in the high intertidal.
Hairy seaweed, Cumagloia andersonii
Turkish washcloth, Mastocarpus (erect phase)
One of the common bladed reds in the upper midlittoral zone. I used to confidently call this wide-bladed form Mastocarpus papillatus. But it turns out, as Druehl and Clarkston (2016) explain, the genus is a complex of variable species. To make things more interesting Mastocarpus also has a black crust life history phase.
Black pine, Neorhodomela
Bleached brunette, Cryptosiphonia woodii
Cryptosiphonia woodii can be turfy or tufty. My experience is that it’s more delicate and goes a lot limper when exposed than Neorhodomela (above). The branch tips supposedly bleach to a blondish color in the summer, which accounts for the common name, bleached brunette. The other common name, dark branching-tube seaweed, isn’t worth mentioning.
Sea sacs, Halosaccion, probably H. glandiforme
I have encountered Halosaccion only on the sheltered shores of the Salish Sea.
Beauty bush, Callithamnion pikeanum
Apparently not too common in northern Oregon, the two featured below are from Bandon, in southern Oregon. Some of the references mention that the branches are often covered with diatoms. I don’t know if the distinctive fuzzy look is due to a covering of diatoms.
Bleach weed, Prionitis
With several species of Prionitis in our area, I’m hesitant to make a specific identification call on this one. When conditions are right it can produce dense growth and a thick somewhat treacherous mat of blades at low tide.
Flat-tipped forked seaweed, Ahnfeltiopsis linearis
I’m pretty sure about the ID here, but like all of these reds, my IDs are open to interpretation. Attractive and photogenic, A. linearis is at home with periodic sand burial. Ahnfeltiopsis was featured in Seaweeds in the Sand.
Turkish towel, Chondracanthus exasperatus
When I see Chondracanthus, it’s usually as drift on the sandy beaches. Chondracanthus was featured in a brief older post, Turkish Towel.
Cryptopleura or Hymenena
Or maybe both! These reds washed ashore in a diverse mass of drift macroalgae. The irridescence stands out pleasingly in the drift line. My identification is tentative and general; please drop me a line if you have identification ideas.
Red sea leaf, Erythrophyllum delesserioides
This fragment washed ashore in a mass of drift macroalgae.
Red wing, Ptilota filicina
There are a few species of delicate fern-like reds in the lower intertidal. The coverage of these in the references cited below is variable and kind of confusing. Thus, identifying most of these with certainty isn’t possible for me. I like the treatment of P. fillicina in Mondragon and Mondragon (2010) and Oregon’s Rocky Intertidal by Kate Krieg.
Succulent seaweed, Sarcodiotheca gaudichaudii
I’ve seen S. gaudichaudii only at low tide on Salish Sea shores.
Red fringe, Smithora naiadum
Cup and Saucer, Constantinea simplex
Always a low intertidal treat.
Mysteries From the Drift Line
Hooked skein, red skein, probably Irtugovia
You’ll see it as Antithamnionella in some of the guides. There are several filamentous reds which are hard to tell apart in photos. Irtugovia is a common epiphyte on bull kelp stipes, so I’m trusting that’s what the image on the left is. Intriguing thin green blades too; Pyropia? The red on the drift timber in the right image gives a similar impression.
A rose red mystery
Rose-purple frills on a purple blade
A lacy epiphyte. This one appeared in my brief post, Epiphytic Reds, a Cherry on Top
Druehl, L. D. and B. E. Clarkston. 2016. Pacific Seaweeds: A Guide To Common Seaweeds of the Pacific Coast. 2nd ed. Harbour Publishing Co.
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.
Online Resources for Reds
Netarts Bay Today – reds.
Biodiversity of the Central Coast – reds.
Seaweeds of Alaska – reds.
And, you can, and should, scroll down to the red algae section of Oregon’s Rocky Intertidal by Kate Krieg.
Give the Seaweed Sorter App a try!