Below you’ll see examples of intertidal red seaweeds, mostly from the 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 a few of them as drift on the beaches. Some are easy to identify with field guides and online resources (see References, below). Others are tricky. I try to get the IDs right, but I’m far from an expert. I apologize for any misidentifications; if you find one, please let me know. There’s nothing new here, just my photos of common reds and a natural history note if I can think of something that hasn’t already been said or seems underemphasized. I show some reds I can’t identify too. Please drop me a line if you can resolve a mystery red.
I more or less follow Lamb and Hanby (2005), showing species in the order they might be encountered on the rocky shore, from highest to lowest in the intertidal. Common names are my choice. I lean on Algaebase for scientific names, and I learn a ton by browsing the pages of Druehl and Clarkston (2016) and Kozloff (1993). All photos are mine, and all are from exposed northern Oregon shores unless noted in the text or captions.
Let’s explore some reds!
Pyropia, nori
There are plenty of species. You’ll see the ones shown here as Porphyra in some of the guides. According to Druehl and Clarkston (2016), most of the Porphyra we encounter in Oregon have been reassigned to Pyropia. Those featured here are common on the high intertidal rocks. Pyropia is rubbery to the touch and somewhat iridescent. A heavy growth can obscure rocky details, making for treacherous footing.
Pyropia on a mid- to high mussel bed | Galiano Island, BC Canada 
Pyropia can completely cover intertidal rocks 
Pyropia will share it’s space 
Where sand burial is prevalent, you’ll sometimes see Pyropia poking out of the sand 
Some forms have short broad blades 
Some forms have long narrow blades 
Dark Pyropia draped over the foreground 
Pale yellow Pyropia 
This patch of Pyropia is rarely submerged, but it gets a lot of splash 
Blades have a rubbery feel and tend to be translucent
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Bangia
You’ll find Bangia on rounded high intertidal rocks, where it looks and behaves like thinning human hair. Bangia is featured in A Brief Account (with Video!) of the Bangia-Human Hair Resemblance.
Look for Bangia on smooth round high intertidal rocks 
Don’t forget Bangia; it’s easy to overlook 
Bangia is sometimes called black sea hair 
Bangia, showing off its true red 
Bangia looks like a limp mop of thinning black hair
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Endocladia muricata, nail brush
Endocladia is one of the common high intertidal tufts.
Endocladia loves the tops of rocks 
Endocladia on the Mytilus bed 
Tiny spines and a wiry hand feel, even when wet, help identify Endocladia 
Endocladia is at home in the barnacle zone 
Endocladia is one of the common tufts of the higher zones
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Gloiopeltis furcata
I didn’t notice this unassuming red ’til I took a closer look at the periwinkles that seemed to like it.
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Cumagloia andersonii, hairy seaweed
A band of Cumagloia andersonii (red) just above Ulva (green); a little Pyropia (blackish) 
Cumagloia andersonii shares upper intertidal space with B. glandula | Good looking June stalks 
You can see why they call it hairy seaweed 
The strands look rubbery, and they are! 
Hairy seaweed seems to love draping over a vertical surface 
You might pass right by Cumagloia andersonii without giving it much notice
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Hildenbrandia, red rock crust, rusty rock
Rich reddish hard brown crusts are a bit of a mystery to me. I think these images feature Hidebrandia. They’re all from fairly low intertidal settings, and they’re hard, resisting indentation by my fingernail.
Sharing space with red blades 
A rich red crust on a low rock wall 
Looks good framed up by corallines | has a spongy look, but it’s hard
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Mazzaella parksii, horn-of-plenty
A fun one to know; it’s another one of those reds that aren’t very red. Look for it on surf-exposed high intertidal rocks. On my home beaches, March through May is a good time to find nice-looking patches.
April is a good month to find Mazzaella parksii 
The base of the blades is deep purplish-red 
M. parksii is sometimes called frilly turf 
M. parksii playing its part in the high intertidal
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Mastocarpus, Turkish washcloth
One of the common bladed reds in the mid to upper intertidal. I used to confidently call the bladed form shown below Mastocarpus papillatus. But 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.
Crust phase; erect phase in the upper left | Galiano Island 
Mastocarpus, sharing high intertidal space with Fucus | Galiano Island 
Papillate and smooth blades | Seaweed Sorter says female Mastocarpus have papillae and males are smooth. 
Wide Y-shaped blade; lower arm curled behind 
Lovely Mastocarpus blades among acorn barnacles
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Neorhodomela
This is Neorhodomela larix, black pine
Black pine can form good-sized patches 
Towards the lower intertidal, Neorhodomela can see seasonal sand burial 
Neorhodomela larix loves nothing more than draping down over its rock
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Cryptosiphonia woodii, bleached brunette
Cryptosiphonia woodii can be dense and turfy or show up as isolated tufts. Only tufts are shown here. It is delicate when exposed and can become limp and matted. The branch tips supposedly bleach to a blondish color in the summer, which accounts for the common name. I haven’t seen much of that.
Cryptosiphonia woodii 
A glorious hanging tuft of C. woodii | Central Oregon 
C. woodii tufts often have a dark, matted appearance 
Floating branches in a finger bowl allows you to see details 
Southern Oregon sunrise illuminates a tuft of Cryptosiphonia woodii
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Microcladia borealis, sea lace
Dark tufts are nondescript from a distance 
Branchlets on one side of the main branch 
Lovely detail in morning light 
Microcladia borealis‘ one-sided branching
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Halosaccion, Sea sacs
The examples below are Halosaccion glandiforme.
A brown, a red, and a green | Orcas Island, WA 
Sea sacs also go by dead man’s fingers | Orcas Island, Wa 
Memories of high tide, limp sacs still partially filled with seawater | Orcas Island, WA 
Halosaccion, with some fellow reds | Central Oregon 
Halosaccion, with sea cabbage in the background | Central Oregon
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Good chance this filamentous tuft is Polysiphonia.
A softball-size tuft of Polysiphonia (identification tentative) | Central Oregon 
A closer look at the filaments (note the tiny photobombing fish) | Central Oregon
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Callithamnion, beauty bush
The images below probably show Callithamnion pikeanum. Some references mention the branches are often covered with diatoms. I don’t know if the distinctive fuzzy look in the images below is due to a covering of diatoms or an inherent fuzziness.
Look for beauty bush in the high and mid-intertidal 
Beauty bush is pure reddish-brown fuzziness 
Callithamnion pikeanum is at home in the mussel beds, and higher
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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.
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Plocamium
I’m not sure what species is/are shown here.
A bit of a mat 
Such a lovely seaweed 
In a finger bowl
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Melobesia, seagrass crust
Easy to find whenever the tide is low enough to expose surfgrass beds. Melobesia can also be found in drifted surfgrass among sea wrack.
Tinge of Melobesia colors the foreground 
Melobesia mediocris on surfgrass 
Pits indicate a mature patch
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Dilsea californica
Dilsea diorama | The lighter red blades are Schizymenia 
Dilsea californica in a typical setting 
I’ve seen Dilsea referred to as leathery strap 
Longer Dilsea californica blades tend to take on a sickle shape 
Dilsea californica is at home is surf exposed settings
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Farlowia mollis
Farlowia mollis, a low tide beauty 
Farlowia laid out to better expose structure (an attempt) 
Farlowia in a small tidepool 
I’ve read Farlowia is sometimes called tattered red seaweed
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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.
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Callophyllis?
A beautiful puzzler, small and erect. Drifted in on the tide
Callophyllis is a starting point here, not a certainty | Galiano Island 
Lovely fan-shaped blades | Galiano Island
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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.
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Mazzaella splendens, rainbow leaf
With its splendid scientific name, common names don’t seem particularly warranted, but besides rainbow leaf, you’ll see splendid iridescent seaweed and iridescent seaweed. Its big blades will give you a lot of looks. Here are a few. Note: M. splendens is variable enough that I’m not going to claim I’m certain these are all M. splendens, but I think they are.
Mazzaella splendens lives up to all its common names 
M. splendens, sharing space on a rock wall 
M. splendens sports a short stipe 
M. splendens | Central Oregon coast
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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.
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Red sea leaf, Erythrophyllum delesserioides
This fragment washed ashore in a mass of drift macroalgae.
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I’m pretty sure the examples below are in that Gracilaria/Gracilariopsis crowd
These are all from semi-protected sand-filled pools on the central Oregon coast
A disturbed clump, showing the base 
You can see the sand-filled bottom of the pool below 
Peering through surface ripples 
Disturbed strands show the branching pattern
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Odonthalia floccosa f. comosa
Not common on my home beaches, this shaggy red threw me for a while. It’s sure a beauty.
Odonthalia floccosa f. comosa, facing the surf, just below the mussel bed | Central Oregon 
O. floccosa f. comosa doesn’t mind draping down a rock face | Central Oregon 
A tuft of O. floccosa f. comosa, off to the right, Endocladia | Central Oregon 
O. floccosa f. comosa‘s lovely locks | Central Oregon
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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.
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Osmundea spectabilis
Osmundea has a pungent odor and a pepper taste; so says Kozloff | Central Oregon 
O. spectabilis goes by red sea fern and sea laurel |Central Oregon 
Morning sun lights up Osmundea‘s blades | Central Oregon 
Wet blades are reflective and maybe a little iridescent | Central Oregon 
Osmundea on an anemone backdrop | Central Oregon
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Succulent seaweed, Sarcodiotheca gaudichaudii
I’ve seen S. gaudichaudii only at low tide on Salish Sea shores.
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Red fringe, Smithora naiadum
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Polyneura latissima
Simplicity is rare among the reds, but we’ll take it where we can get it. Any Polyneura encountered on Pacific northwest shores is P. latissima.
Polyneura, exposed at low tide 
Crisscross veins is a characteristic of Polyneura latissima 
Polyneura latissima is the only species of Polyneura in our area
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Cup and Saucer, Constantinea simplex
Always a low intertidal treat.
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Something approximating Antithamnionella, red sea skein
If indeed it is Antithamnionella, you’ll see it as Irtugovia in some of the guides. It also goes by hooked or red skein. There are several filamentous reds which are hard to tell apart from photos alone. Antithamnionella a common epiphyte on bull kelp stipes, so I’m trusting that’s what at least two of these images show. They all seem to have the same look so I’ve lumped in the reds on the drifted timber too.
Delicate epiphytes on a bull kelp stipe 
An eye-catching red adorns a drift timber 
Drift bull kelp is aways worth a closer look
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Mysteries From the Drift Line
A lacy epiphyte that gives a much different impression than Antithamnionella (above). There’s a decent chance it’s Pterochondria woodii.
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A rose red mystery
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Rose-purple frills on a purple blade
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References
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.
Give the Seaweed Sorter App a try!
Note: This page was updated on Feb 13, 2020.
