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Smithora naiadum
Seagrass Laver
Alaska to Mexico
Family Erythrotrichiaceae

Smithora naiadum (the genus is named after Gilbert M. Smith who authored “Marine Algae of the Monterey Peninsula”, and the species name is derived from Latin for “water nymph”) is a delicate red-algal epiphyte on the seagrasses Zostera and Phyllospadix.  It is pictured here on Zostera.  The wine-red blade is monostromatic (it is one-cell thick) and wedge-shaped, broader at the tip and narrowing toward the holdfastPyropia  another thin-bladed alga, may also grow on seagrasses, but Smithsora can be identified by its discoid attachment to the seagrass instead of by the rhizoidal cells that secure Pyropia.  You can find Smithora on Zostera in Netarts Bay and on Phyllospadix on wave-swept rocks during summer months.
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Bossiella schmittii
California Winged Coral Seaweed
British Columbia to southern California
Family Corallinaceae

Formerly Bossiella californica, this erect, jointed coralline algae resides in wave swept, rocky, lower intertidal and subtidal zones.  It has an irregular dichotomous branching pattern, which means its branches are sort of dichotomously arranged.  The thallus is composed of pink to purple, calcified segments (called intergenicula in seaweed keys) shaped like flattened wing nuts and lined up end to end.  Segments of B. schmittii are generally two or more millimeters in length.  When reproductively active, each will have two to four conceptacles, the bumps you see on the surface of the wings.  This arrangement of conceptacles distinguishes Bosiella from Calliarthron which has conceptacles along the margins of its segments. 
Bossiella dichotoma
Winged Coral Seaweed
British Columbia to Mexico
Family Corallinaceae

This Bossiella can be abundant in the mid intertidal zone, growing on the upper sides of large rocks.  It also has irregular dichotomous branching.  Its segments are smaller than B. schmittii, a millimeter or less in length, and there usually two (sometimes three or four) conceptacles on each when the alga is reproductive.  This specimen was collected from Tunnel Beach during late October.  There are currently a couple of subspecies described Gabrielson et. al. (2012).

Sponsored by the Friends of Netarts Bay Watershed, Estuary, Beach and Sea (WEBS)
Corallina vancouveriensis
Graceful Coral Seaweed
Aleutian Islands, Alaska to Mexico
Family Corallinaceae

This delicate coralline is found in the same local as Bossiella, where they often grow next to each other.  It is pinnately branched. Its segments are fairly cylindrical, a millimeter or less long, without wings, and few if any conceptacles.  Each segment of the main axis has two branches, one on each side.  These segmental characters distinguish C. vancouveriensis from other species of Corallina.
Melobesia mediocris
Seagrass Crust
British Columbia to Baja Califonia
Family Corallinaceae

This crustose coralline alga is easy to identify because it only occurs as an epiphyte on the seagrasses Zostera and Phyllospadix. It is pictured here on Phyllospadix. It grows as small round patches that enlarge and push against each other until they finally coalesce into a dense coating. The small holes in the surface lead to male and female conceptacles.  The conceptacles may be multiporate.
 
Crustose coralline algae
Family Corallinaceae

Coralline algae come in two different characteristic modes of growth - erect or encrusting.  The coralines describe above are the erect kind.  The encrusting ones, or crustose algae as they are called, can be seen at almost any low tide covering rocks, shells, and other hard substrates, looking like patches of crusty pink paint.  They include genera such as Mesophyllum, Lithophyllum, Melobesia, Pseudolithophyllum, Lithothamnion, and others, difficult to identify without a microscope.  Coraline algae contain deposits of calcium carbonate in their cell walls.  In spite of their appearance and calcium carbonate, they like other coralines, are photosynthetic and contain chlorophyll.  Their knobby surfaces conceal reproductive conceptacles.  These kinds of algae are cosmopolitan, occurring in all seas.
Halosaccion glandiforme
Sea Sacs
Aleutian Islands, Alaska to Point Conception, California
Family Palmariaceae

These hollow, yellowish-brown to red thalli look like slightly inflated fingers of a latex surgeon’s glove.  They are yellowish when growing in sunlight, redder when in the shade.  The sacs are filled with seawater, admitted through pores in the sac wall, except for a bubble of oxygen in the tip, produced by photosynthesis.  Halosaccion inhabits rough, wave-swept rocks in the mid intertidal zone.  The water in the sacs keep the alga cool when exposed to sunlight at low tide.  A thin stipe attaches each sac to a small discoid holdfast.  The aerodynamic shape of the thallus allows Halosaccion to resist being detached from rocks in heavy surf.  I have yet to find Halosaccion growing between the Capes, probably because I can't get out to where it is growing, but it is commonly washed ashore and can be found while walking the beaches.
Neoptilota hypnoides
Sea Fern
Alaska to central California
Family Ceraminaceae

The Sea Fern is an uncommon red alga from the mid to low intertidal zones that grows on rocks or is epiphytic on coralline algae.  The one pictured here was found on wave-swept rocks off Tunnel Beach.  It has a flat, bipinnate thallus with alternately arranged branches, the primary branches stemming from a central midrib.  The ultimate branchlets are small and blade-like with smooth edges, which distinguish this Neoptilota from other species whose ultimate branchlets are serrated.  In the lower photograph, you can see short fertile branchlets alternating with sterile branchlets.

Cryptopleura ruprechtiana
Hidden Rib
Alaska to Baja California
Family Delesseriaceae

The genus Cryptopleura is Greek for “hidden rib”.  A distinct midrib at the base of this rose-red alga fades into a network of faint to microscopic veins toward the upper parts of the thallus.  The blades, thin and deeply divided, are fringed with outgrowths or ruffles at the middle and bases of the lobes.  Reproductive structures may reside in the fringes.  It can be fairly abundant on the outer rocks along Tunnel Beach, growing where surf can be heavy. 

The actiual species may be in doubt.  Dr. Gayle Hansen (Oregon State University) identified Cryptopleura violacea in Netarts Bay.  Gabrielson et. al. (2012) said that all species in the local area need critical study.

Neorhodomela larix
Black Pine
Alaska to Baja Califonia
Family Rhodomelaceae

Neorhodmela larix, a course red alga, blackish brown in color, has short side branchlets in clusters like needles on a larch tree (hence the species name larix) growing spirally on a central stem.  It is common on rocks in the higher intertidal zone, often where waves beat the shoreline.  It is a perennial that dies back during winter, but grows rapidly in spring and summer.  It has an isomorhic life cycle, meaning that the gametophyte looks identical to the tetrasporophyte.  It is another alga that periodically gets covered by sand but still survives and resumes growth after it emerges from burial.  There is speculation that periodic covering may discourage herbivores, such as the black chiton Katharina tunicata, that do not tolerate sand.  This species can survive a wide range of temperatures.

There is a similar species, Neorhodmela oregona, Oregon Pine, that lives mainly in tidepools.  Its more flexible than Black Pine and its branching is indeterminite,
Odonthalia floccosa
Sea Brush
Aleutian Islands, Alaska to central California
Family Rhaodomelaceae

Odonthalia floccosa (the genus, from Greek, means “toothed twig”; the species, from Latin, means “flock of wool” ) is a member of the phylum Rhodophyta, the red algae, even though it appears more brownish than red.  Sea Brush typically occurs on rocks where there is moderate wave action or, sometimes, in more protected waters.  I have found it lining tide pool edges fairly high in the intertidal zone.  One such pool is in the basalt rocks near the man-made arch between Tunnel Beach and Lost Boy Beach.  Another is a large pool on the rocks at the north end of Short Beach. O. floccosa is a profusly branched alga.  Secondary branches alternate off the main stem, which is little more than a millimeter in diameter.  Tertiary branchlets are pretty much equal in length.  The tips of female gametophyte individuals may have a cluster of tertiary branchlets, called calcars, which surround a cystocarp, the structure that contains female reproductive cells, the carpogonia.  The entire thallus may grow to more than a foot in height before being knocked back in winter.  One way of telling O. flaccosa from other species of Odonthalia is that the branches are not flattened.  They are almost round in cross section.

Gabrielson et. al. suggests that O. floccosa may include two distinct species and needs to be re-examined.
Pyropia lanceolata (complex)
Laver, Nori
Alaska to Mexico
Family Bangiaceae

In 2011, Porphyra was split into several genera, and now most in our area are in the genus Pyropia.  The species pictured here is lives in the middle and upper tidal zones, is greenish-brown, monostromatic - the thallus is only one cell thick - and, each cell has one plastid.  It was prevalent in spring and early summer.  It may be P. lanceolata, which has these characters, but so do other species.  Lindstrom et. al. (2015) recognize seven distinct species in this complex or clade (a group of biological taxa that includes decendents from a common acestor) from the west coast of North America that are morpholgically similar but are different genetically and live in different ranges and habitats.

It likes sunlight and grows on the tops and upper sides of rocks, and blades may reach over a foot long. It can withstand almost total dehydration.  Known as Nori in Japan,  Pyropia is edible and nutritious, and some species are tasty, giving rise to a huge aquaculture industry in the Far East.  Japanese use dried Nori as a wrap for their cookies, crackers, and sushi.  Our Pyropia here, while edible, is a bit on the rubbery side with a slight salty taste.


Pyropia smithii
Laver, Nori
British Columbia to central California
Family Bangiaceae

In 2016, Pyropia smithii and P. pulchra were determined to be the same and given the former name.  It is a pinkish-violet, monostromatic, epiphyte, in this case growing on a Laminarian, but will live on other algae and the sea grass Phyllospadix as well.

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Polysiphonia hendryi
Poly Gardner
Alaska to Mexico
Family Rhodomelaceae

There are several varieties of Polysiphonia hendryi, this one possibly P. hendryi var.gardneri.  It is common on rocks, often in the upper intertidal area.  A microscope or a good hand lens is required to identify the Polysiphonias.  In this case, there is an elongated central cell surrounded by 10 to 12 brick-shapped pericentral cells.  It is highly branched, forming reddish tuffs.

Polysiphonia is cosmopolitan with around 200 species.  It is probably one of the most studied of the red algae, especially by students taking marine phycology courses because it is relatively easy to collect the major parts of its life cycle.  The name is derived from Latin means “many tubes”, and as you can see from the micrograph, the thallus consists of stacks of narrow, cylindrical cells.  Each “segment” contains a central axial cell surrounded by equal length pericentral cells.  Some species may have as few as four pericentral cells; others such as P. hendryi have more. The branches are narrow, less than a millimeter or two in diameter, so microscopic examination is required to properly identify a species.  The alga is colored red because it contains the pigment phycobilin which masks the green chlorophyll.  Tetrasporophytes and gametophytes are isomorphic, that is they look the same, except for their reproductive structures.  Tricoblasts, which are colorless filamentous branchlets that arise from apex of the thallus, can be seen at the tips of the branches (third picture). P. hendryi can be found attached to rocks and shells at mid to lower tide levels.

Pericentral cells
Tricoblasts
Polysiphonia hendryi var. deliquescens
Poly
Alaska to California
Family Rhodomelaceae

As metioned above, there are several varieties of Polysiphonia hendryi.  This one, P. hendryi var. deliquescens, is common near the entarace of Netarts Bay, just below the Terrimore Motel.  Branches are several inches long, lacy, and described in the keys as "lax", that is there is no stiffness to them and the droop when collected.
Constantinea simplex
Cup and Saucer Seaweed
Alaska to Point Conception, California
Family Dumontiaceae

This unusual looking and easily recognized red alga with its cup-shaped blade grows on lower intertidal and subtidal rocks.  This one was found during a very low summer tide on some low lying, wave-exposed, outer rocks just northwest to Maxwell Point.  It is a perennial with a single stipe that produces a new blade yearly.  A small nubbin in the center of the blade develops into a new stipe above the existing one during the summer.  In the fall a new blade is formed on the new (or extended) stipe, and the older blade erodes away during the winter.  The age of the alga can be determined by counting the number of blade scars on the stipe.

Extracts from C. simplex have been investigated for drug use, including antiviral properties. An isolated structural polysaccharide may provide relief from herpes and other viral infections.
Cryptosiphonia woodii
Bleached Brunette (An Alaskan name)
Alaska to central California
Family Dumontiaceae

The common name refers to this red alga turning a dirty blond late in the summer. We can find it growing in tufts on rocks in the mid tide zone, where it can be abundant during late spring and summer. The sporophyte and gametophyte generations are isomorphic, and gametophytes have separate sexes. The thallus, stemming from a discoid holdfast, is highly branched. Branches are tapered at their tips and bases.

Like Contantinea, and Farlowia, aqueous extracts of Cryptosiphonia have promise as a treatment for herpes. The active ingredient is believed to be a polysaccharide.

Farlowia mollis
Farlow’s Seaweed
Alaska to Baja California
Family Dumontiaceae

Farlow’s seaweed is a dark red alga with flattened, ribbon-like branches that can be found along the edges of some of the tide pools at Tunnel Beach.  Branching is mainly distichous, that is it has branches on two sides of a main axis, but the branching is fairly irregular, making the alga look weathered.  The terminal branches may become more cylindrical.  It grows on rocks (“saxicolous” is the technical term for “growing on rocks”), and it is another alga that can withstand being buried in sand.  The genus is named after William Gilson Farlow, a professor of cryptogamic botany at Havard University, who published on fungi, algae, and plant diseases.  Farlowia mollis has recently been examined as a source of various pharmaceuticals and unusual biochemicals produced by this alga, including those that have antiviral properties.

Endocladia muricata
Sea Moss, Nail Brush Seaweed
Aleutian Islands, Alaska to Baja California
Family Endocladiaceae

This seaweed, a frequent food for the limpets that cling to rocks high out of the water, lives in the upper intertidal region, mostly in the splash zone.  It attaches to rocks, California mussels, barnacles, and almost any hard surface by a small, discoid holdfast.  It grows as profusely branched tufts and, where dense enough, will form wiry mats.  Its branches are cylindrical and covered with short, soft spines.  When wet, it a yellow to reddish brown.  When dry - and this seaweed can desiccate until it is almost crisp - it is a brownish black.  It likes sunlight, can withstand high variations in temperature, and it is usually exposed to air and sun much of the day when it can lose a good portion of its water yet still photosynthesize.  Its sporophyte looks identical to its gametophyte (the generations are isomorphic).
Chondracanthus exasperatus
Turkish Towel
Southeast Alaska to Baja California
Family Gigartinaceae

This red alga sometimes washes up on the beach between Netarts and Oceanside and can be found growing in the cobbled shallows just south of Happy Camp in Netarts Bay.  Its distinctive rough surface reminds one of a bath towel, hence the common name.  It has a small discoid holdfast that supports several oblong or lanceolate, brick-red to purple-red blades, each of which may reach more than a couple feet in length, and each with a short stipe.  Both sides of a blade are covered with small, pimple-like bumps, the papillae, that often, but not always, harbor reproductive structures.  The blades of sporophyte and gametophyte generations are isomorphic, which means they look the same and can only be identified by microscopic examination.  Early guides place Chondracanthus in the genus Gigartina.

Mazzaella oregona
Northern Mazza Weed
Southern Alaska to Ventura, California
Family Gigartinaceae

The blade of this Mazzaella are irregular, divided, lobed, and often covered with large bumps, the cystocarps, which are reproductive structures common to most red algae.  Cystocarps produce carpospores, spores that are diploid (having a double set of chromosomes) and germinate to give rise to free-living individuals, the tetrasporophytesM. oregona may have a short stipe or it may be sessile.  Its color can vary from yellow-brown to reddish brown.  It can be common on rocks in wave-exposed habitats, usually in the mid to upper intertidal zone.  It was formerly named M. heterocarpus and Iridaea heterocapus, names you may find in older seaweed guides.

Mazzaella parksii
The Horn of Plenty Alga
Aleutian Islands, Alaska to northern California
Family Gigartinaceae

Until recently known as M. cornucopiae, the horn of plenty alga lives between the Capes in the wave-pounded rocks of the middle-to-high intertidal zones where it forms a dense turf of curled, often lobed blades usually less than two inches long.  It propagates vegetatively from a perennial encrusting holdfast, and, if broken apart from the rest of the thallus, can survive on its own.  Because of this potential for independence, M. parksii is known as a “clonal” alga.  The blades range in color from a light yellow-green (as shown here) to a brownish-purple.  Its vertical distribution in the intertidal zone is determined by physiological stress in it upper reaches - heat and desiccation - and by herbivores such as snails at its lower limit.  It prefers north-facing slopes which avoid direct sunlight.  It can also be found in the western Pacific from Japan to Eastern Russia.  I found these specimens on the rocks between Tunnel Beach and Lost Boy Beach.
Mazzaella splendens subsp. fulgens
Iridescent Seaweed, Rainbow Leaf
Southeast Alaska to Baja California
Family Gigartinaceae

This leafy red seaweed is easily identified when wet by its iridescent sheen.  It shows rainbows of blues and reds against its natural wine-colored background.  The iridescence is caused by the selective reflection of white light by the varying thicknesses of a cuticle on the surface of the blade, much in the way a film of oil on water becomes iridescent.  It is found in both in wave-prone and sheltered rocky habitats, usually in the mid intertidal to subtidal zones.  Those pictured here were photographed under water at Netarts, near the mouth of the bay.

This alga and other reds contain a carraeenan, a gelatin-like substance in its cell walls that is extracted for commercial purposes and used as a smoothing and thickening material in toothpaste, ice cream, puddings, paints, and other products.

Carrageenan can also be used in identification of the alga’s isomorphic reproductive phases.  Mazaella spendens has isomorphic gametophyte and tetrasporophyte stages that are difficult to visually distinguish but can be characterized by several kinds of analyses, one of which is a simple colorimetric chemical test.  The chemical, resorcinol, a phenolic compound, is used to identify different kinds of carrageenans (kappa-carrageenan in the gametophyte and lambda-carrageenan in the tetrasporophytes).

Tetrasporophyte and gametophyte phases can form their own populations that vary with seasons, the amount of shelter from or exposure to surf, and other factors.  Studies of the environmental influences that cause the dominance of one phase over the other rely on this kind of analysis.

Callophyllis sp.
Violet Sea Fan
Alaska to Baja California
Family Kallymeniaceae

This is one of those leafy red algae that are difficult to identify in the field.  The surest way to determine the genus is to examine a thin cross section of the blade with a microscope.  The medulla (the inner core of the blade) of Callophyllis has large cells dispersed among chains of small cells.  The Callophyllis pictured here is probably C. flabellulata.  Macroscopically, the blades are not fleshy, have no midribs or veins, no stipe, but do taper into a discoid holdfast.  The ends of the blades have rather ragged branches or notches.  It grows locally on rocks in the mid to lower intertidal zone.


Mastocarpus papillatus
Turkish washcloth
Queen Charlotte Islands, British Columbia to Southern California
Family Phyllophoraceae

Mastocarpus papillatus has a complex life history that puzzled phycologists until the 1970s when the alga was cultured and the various reproductive stages, which do not resemble each other, were identified.  The stage pictured here is the female gametophyte.  It is dark red-brown to almost black.  The blades are dichotomously branched, covered with papillae, and grow up to 6 inches long.  The papillae, the small bumps on the surface of the blades, are cystocarps which give rise to carposporophytes that have their own morphology.  The male gametophyte has no papillae, is yellow to light pink, and has a thinner blade.  The most confusing stage is the tetrasporophyte, once thought to be a different alga altogether called Petrocelis franciscana.  It is encrusting and looks like a patch of soft tar on a rock.  Once the life cycle was worked out, it became the “Petrocelis stage” of Mastocarpus papillatus, but is now just called the tetrasporophyte.  This alga lives in the mid to high intertidal zone.  It can undergo considerable desiccation, and it can withstand high temperatures.  Locally, it is common on the rocks on the south side of Short Beach, near the north entrance to Lost Boy Cave.

Ahnfeltiopsis linearis
Flattened Ahnfelt’s Seaweed
Southern British Columbia to Point Conception, California
Family Phyllophoraceae

Named after a Swedish botanist, Nils Otto Ahnfelt, this cartilaginous-feeling, dichotomously branched seaweed inhabits tops and upper sides of the lower profile, sand-impacted rocks in the middle intertidal zone, especially along Tunnel Beach.  It branches primarily in a single plane, making the thallus rather fan-shaped.  Its outer branches are slightly flattened, rather oval in cross section, but the base of the thallus is round.  It can be a deep maroon near the base, but lighten after the second dichotomy.  The tips of older thalli may bleach to almost white. Its holdfast is disk-shaped and unbranched.  Tunnel Beach is part of a pocket beach where the sand moves in and out, sometimes covering rocks, other times exposing them. Ahnfeltiopsis is frequently buried and can remain alive under the sand for over six months.  This seaweed used to be known as Gymnogongrus linearis.

Ahnfeltiopsis gigartinoides
Loose Ahnfelt’s Seaweed
Alaska to Mexico
Family Phyllophoraceae

A. gigartinoides has a crustose sporophyte (tetraporophyte) and an upright gametophyte.  The semi-dichotomous branches are narrower and more rounded than it intertidal counterpart, A. linearis.  It is attached to rocks in the lower and sub-tidal zones and is often buried in sand.  It is dark red to almost black and may grow up to ten inches tall.
Dilsea californica
Leathery strap seaweed, California red blade
Alaska to California
Family
Dumontiaceae

This deep maroon to brownish-red colored seaweed is common in the rocky mid-to-low intertidal area along Tunnel Beach near Oceanside.  Microscopic examination of a cross section of the blade revealed that the medulla (the inside of the blade) is composed of randomly arranged filaments, and chains of cells occupy the cortex.  Filaments are characteristic of Dilsea. Haploid and diploid phases are isomorphic. The blades are broadly lanceolate, the holdfast is discoid, and it attaches to rocks.

Cross section of blade (thallus)
Diagram of a thallus cross section. From Abbott and Hollenberg 1976
Prionitis filiformis
No Common Name
Southern Alaska to Baja California
Family Halymeniaceae

This mid-to-low intertidal red alga seems to be fairly rare locally, but can be found on the rocks between Tunnel Beach and Lost Boy Beach.  The narrow, wiry thalli may be 12 inches long or more, dark red in color, somewhat dichotomously branched with the ends of the branches frequently flattened.  It is saxicolous (attached to rocks) but lives in areas impacted by sand.   When crushed, it can release a bleech-like smell.

Prionitis sternbergii
Bleachweed
Southern British Columbia to Baja California
Family Halymeniaceae

Prionitis sternbergii is common during summer around the edges of rocky tide pools and in quiet areas, and we find it near the entrance of Netarts Bay in the cobbles below the Terrimore Motel.  Its main axis can be wide or narrow, but the flatted, strap-like secondary blades can be more than an inch across.  They may be decorated with small, tertiary, pinnate outgrowths.  Its color can range from dark red to a light brownish-yellow as pictured here.  It may smell like household bleach. It is morphologically diverse, and its form may vary with geography.

A similar species, P. lanceolata, grows on unprotected wave-swept coasts.

Gracilaria / Gracilariopsis
Red Spaghetti, Sea Spaghetti
Alaska and Canada to Mexico
Family Gracilariaceae

Gracil (Latin) means thin or slender.  These two genera of spaghetti-looking algae can only be identified by their reproductive structures, for example whether the spermatangia of the male alga are in pits or whether they are borne in a continuous superficial layer of the thallus.  This kind of examination requires a microscope.  For this reason, most field guides, as will this one, group these two genera together.  The two probable species that may occur in our area are Gracilariopsis andersonii and Gracialria pacifica.

Examples shown here, one lying on the beach (upper photo), the other in shallow water, were growing attached to cobbles buried in sand near the entrance of Netarts Bay.  The holdfast is small and discoid.  The thallus is reddish when young but turns yellow-brown as it ages.

Gracilaria textorii
Kabonori
Distribution?
Family Gracilariaceae

Not all Gracilaria are round and spaghetti-like.  Some are flat . The blades of Gracilaria textorii are uniformly flattened and dichotomously branched.  The medulla (the inner part of the blade) is composed of large, similarly-sized cells.  The raised bumps on the thallus shown in the photographs are probably cystocarps.  The holdfast is discoid, and the alga grows on rocks.  Gabrielson, et. al. (2004) say this species has not been reported norh of San Luis Obispo County in California.  This specimen was collected near the entrance of Netarts Bay.


Cross section of blade
Plocamium pacificum
Sea Comb
Southeastern Alaska to Baja California
Family Plocamiaceae

This deep pink to rose-red alga is common on upper and lateral surfaces of rocks in the mid to lower intertidal zone and will extend into subtidal regions.  It is abundant at Tunnel Beach where it tolerates being covered by sand.  It has a flattened, cartilaginous thallus with successive branchlets, the outer ones branching from one side only, like a comb.  Many of the branchlets are slightly curved (the genus is derived from the Greek word “plokos” meaning “curl”).  It often grows from prostrate stoloniferous branches.

This algae has also been called  Plocamium pacicficum.


Irtugovia pacifica
Hooked Skein
Alaska to Mexico
Family Ceramiaceae

This delicate rose-red alga may grow on rocks, but it also is common on the stipe of the bull kelp Nereocystis leutkeana and other large brown kelps.  It is distinguished by the ends of its branches being somewhat S-shaped (sinusoidal), having no gland cells, and stalked tetrasporangia.  Branchlets are usually unbranched and opposite. When growing on kelp, branches of its holdfast will penetrate the tissues of the host's stipe.  The alga is dioeceous, male and female gametophytes are separate.  Abbott and Hollenberg (1976) list two varieties: A. pacifica var. pacifica and A. pacifica var. uncinata. The third figure shows a stalked tetrasporeangium.


Callithamnion pikeanum
Beauty Bush
Alaska to California
Family Ceramiaceae

You can find beauty bush high in the intertidal zone, the splash zone, on rocks at Tunnel Beach and Short Beach.  It is easy to recognize by its wooly appearance due to its dense branching.  It is a filamentous red whose main axis is heavily corticated, and there may be several axises arising from a common holdfast.  It is described as being colored from purplish brown to tan and up to sixteen inches long.  In our area it seems to be tannish and mostly one to three inches long.  Tetrasporangia form on the upper sides of the outer filaments, the side toward the axis.  The Greek meaning is “beautiful shrub.”


Bangia sp.
Black Sea Hair
Aleutian Islands to Costa Rica

Bangia sp. appeared on the tops of bolders during April 2016 beween Oceanside and Netarts.  It is a filamentous, cylindrical, purpleish-brown seaweed that is considered, along with other members of the family, an evolutionarily primitive red alga because it lacks certain structures found in most other reds.  It attaches to rocks with a peculiar discoid holdfast that is formed by the lower cells of the filament growing rhizoidous-like extensions downward that group together to create the holdfast.

Where Bangia was dominant on these rocks in the spring of 2016, it was sparse in April 2017.  The dominant algae became Pyropia and Ulva.


Micrograph of filament
Rhizoidous-like cell extensions (faint gray lines running along the filament) leading to the holdfast at the left.
Hymenena flabelligera
Black-lined Red Seaweed
Alaska to central California
Family Delesseriaceae

As Louis Druehl points out in his guide “Pacific Seaweeds”, the genus Hymenena can be confused by beginners with the genera Cryptopleura and Botryoglossum.  There are distinct similarities. They are all in the family Delesseriaceae, and if you look at the illustrations in “Marine Algae of California” by Abbott and Hollenberg, you will see their physical resemblance to each other.  The blades are flat, thin, similarly branched.  You will also see differences in the reproductive structures, but they occur only in the sporophyte (technically, the tetrasporophyte) where the sori are in different locations. Hymenena flabelligera has longitudinal lines of sori running from the base of the thallus almost to the ends of the divided tips.  Its thallus is usually longer than 6 inches. It grows on rocks in low intertidal to subtidal zones.  The specimens pictured here were found on the cobbled bottom of Netarts Bay near Happy Camp.

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