Red Algae, Rhodophyta

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.

Pyropia on a high intertidal rock

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, it’s host rock buried well below

Pyropia, exposed at low tide

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Bald sea hair, Bangia 

Look for Bangia on smooth round high intertidal rocks

Bangia looks like a limp mop of thinning black hair

Don’t forget Bangia; it’s easy to overlook

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Nail brush, Endocladia muricata

Also called sea moss, Endocladia is one of the common tufts in the high intertidal.

Endocladia loves the top of a flat rock

Tiny spines and a wiry hand feel, even when wet, help you identify Endocladia

A tuft of Endocladia amongst the Phaeophyta

Endocladia on the Mytilus bed

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Hairy seaweed, Cumagloia andersonii

Cumagloia andersonii shares upper intertidal space with B. glandula | Good looking June stalks

You might pass right by Cumagloia andersonii without giving it much notice

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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.

Warty and smooth blades

Sharing space with Ulva and Endocladia

A spring growth of Mastocarpus

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Black pine, Neorhodomela

Black pine, Neorhodomela larix, around and under sea cabbage on an exposed south facing rock wall; surfgrass at lower right

Neorhodomela larix is the most common Neorhodomela in Oregon

If you look closely you can see the branchlets are arranged in spirals

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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.

Cryptosiphonia woodii in the upper midlittoral

Crytopsiphonia woodii

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Sea sacs, Halosaccion, probably H. glandiforme

I have encountered Halosaccion only on the sheltered shores of the Salish Sea.

A brown, a red, and a green | Orcas Island, WA

Sea sacs also go by old man’s fingers | Orcas Island, Wa

Memories of high tide, exposed sea sacs are filled with seawater | Orcas Island, WA

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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.

Tuft of beauty bush, Callithamnion pikeanum, upper center | southern Oregon

Beauty bush, Callithamnion pikeanum, center | southern Oregon

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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.

Nice layer of Prionitis in the foreground

A pleasing scene of low tide reds

Prionitis, exposed at low tide

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Plocamium

Up close, Plocamium’s a beauty

Plocamium, this one anyhow, can for a thick carpet.

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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.

A rarely exposed grove of Ahnfeltiopsis, northern Oregon, May 8, 2016

When conditions are right Ahnfeltiopis linearis can form a hairy carpet

Forked seaweed, I’ll buy that – Ahnfeltiopsis is always flirting with sand burial

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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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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.

Deeply divided blades with frilled margins, and irridescence

Distinctive veins on divided blades

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Red sea leaf, Erythrophyllum delesserioides

This fragment washed ashore in a mass of drift macroalgae.

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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.

Ptilota filicina draped over over Codium

Which common name suits, red feather or red wing?

Succulent seaweed, Sarcodiotheca gaudichaudii

I’ve seen S. gaudichaudii only at low tide on Salish Sea shores.

Low tide exposes Sarcodiotheca gaudichaudii among cobbles, gavel and seashells | Orcas Island, Washington

A drifted tuft of Sarcodiotheca gaudichaudii | Orcas Island, Washington

Known by some as suculent seaweed, it’s scientific name is so much more interesting |Orcas Island, Washington

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Red fringe, Smithora naiadum

Red fringe, Smithora naiadum on surfgrass in a low sand-filled tide pool

Red fringe, Smithora naiadum on drift surfgrass

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Cup and Saucer, Constantinea simplex

Always a low intertidal treat.

A sheltered niche suits Constantinea simplex

Cup and saucer, Constantinea simplex

In a lot of Constantinea simplex photos you’ll see surfgrass

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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.

Epiphytes on bull kelp stipe

In the wrack line, an eye-catching red adorns a drift timber

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A rose red mystery

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Rose-purple frills on a purple blade

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A lacy epiphyte. This one appeared in my brief post, Epiphytic Reds, a Cherry on Top

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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.

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!