Brown Seaweeds

Division Heterokontophyta

 

HAWAII

Asteronema breviarticulatum

Makapu'u intertidal, Oahu

Portlock, Oahu

Found as tufts on shaded vertical surfaces in the splash zone.

Chnoospora minima

Makapu'u intertidal, Oahu

Makapu'u intertidal, Oahu

Found on rocky coasts exposed to breaking waves.

Nemacystus decipiens

Makua, Oahu, 20 feet

Makua, Oahu, 20 feet

A slippery species found during summer on rocks at any depth.  Attains 16 inches.  Hawaii & the Indo-Pacific.

Colpomenia sinuosa

Makapu'u tidepool, Oahu

 

Makapu'u tidepool, Oahu

Black Point, Oahu

Black Point, Oahu

Common on reefs to at least 80 feet.  Hollow.

Dictyota acutiloba

Ft. Kamehameha, Oahu, 3 feet

 

Ft. Kamehameha, Oahu, 3 feet

Makua, Oahu, 15 feet

 

Makua, Oahu, 15 feet

Makua, Oahu, 15 feet

 

Makua, Oahu, 15 feet

Makua, Oahu, 15 feet

Common on sandy reef flats.  Blades are thin and twisted.

Dictyota ciliolata

Kapoho Point, Kailua, Oahu

 

Kapoho Point, Kailua, Oahu

Kapoho Point, Kailua, Oahu

Common on shallow reefs.  Yellow-green blades are flat and edges lack denticles.

Dictyota ceylanica

Makapu'u tidepool, Oahu

Common in turfs on rocks in shallow water.  Blades are less than 2mm wide.

Dictyota friabilis

Baby Barge, Oahu, 70 feet

 

Baby Barge, Oahu, 70 feet

Black Point, Oahu

Black Point, Oahu

Common on shaded surfaces at any depth.  Tips form a Y pattern.

Dictyota sandvicensis

Kapoho Point, Kailua, Oahu

Kapoho Point, Kailua, Oahu

Black Point, Oahu

 

Black Point, Oahu

Kapoho Point, Kailua, Oahu

Common on shallow reefs.  Yellow-green blades are flat and edges have denticles.

Dictyopteris australis

A large species abundant on sandy reefs in deeper water.    Midrib present with brown spots forming 'V' marks with apex toward tip of blade.

Dictyopteris plagiogramma

Makapu'u, Oahu, 15 feet

 

Makapu'u, Oahu, 15 feet

Makapu'u, Oahu, 15 feet

A small species abundant on rocky shores exposed to wave action.  Midrib present with brown spots forming 'V' marks with apex toward base of blade.

Hydroclathrus clathratus

Makapu'u tidepool, Oahu

Occasional on rocky shores exposed to wave action.

Lobophora variegata

Makapu'u tidepool, Oahu

 

Makapu'u tidepool, Oahu

Makapu'u tidepool, Oahu

Abundant on shaded surfaces.  Brown or orange with free edges.  Stiff and lightly calcified.

Padina australis

Makapu'u intertidal, Oahu

 

Makapu'u intertidal, Oahu

Makapu'u intertidal, Oahu

Makapu'u intertidal, Oahu

Abundant on quiet sandy reefs.  Blades are several inches wide with torn margins.  Lightly calcified. 

Padina gymnospora

Ft. Kamehameha, Oahu, 3 feet

A large lightly calcified species uncommon on sandy reef flats.

Padina sanctae-crucis

Makapu'u tidepool, Oahu

 

Diamond Head, Oahu

Diamond Head, Oahu

Abundant on rocks in shallow water exposed to wave action.  Well-calcified and about 1 inch wide.

Padina melemele

Firehouse, Oahu, 40 feet

 

Firehouse, Oahu, 40 feet

Firehouse, Oahu, 40 feet

Quite rare in shaded areas at scuba depths.  Stiff, well-calcified with dark yellow color.  1 inch wide.

Rosenvingea intricata

Makapu'u tidepool, Oahu

Makapu'u tidepool, Oahu

A delicate seaweed that is rare in shallow water and tidepools.

Sargassum echinocarpum

Makapu'u tidepool, Oahu

 

Makapu'u tidepool, Oahu

Makapu'u tidepool, Oahu

Abundant on reefs exposed to wave action.  Blades are broad, thick and spiny.

Sargassum obtusifolium

Mokuleia tidepool, Oahu

 

Mokuleia tidepool, Oahu

Makapu'u tidepool, Oahu

 

Makapu'u tidepool, Oahu

Makapu'u tidepool, Oahu

Abundant on reefs exposed to wave action.  Blades are thin, narrow, and elongated.

Sargassum polyphyllum

Makapu'u intertidal, Oahu

 

Makapu'u intertidal, Oahu

Makapu'u intertidal, Oahu

Makapu'u intertidal, Oahu

Abundant on reefs exposed to wave action.  Blades are narrow, short, and undulated.

Ralfsia expansa

Black Point, Oahu

Forms dark crust on rocks in the intertidal & shallow subtidal.  Warm seas worldwide.

Sphaecelaria sp.

Makapu'u tidepool, Oahu

Found in tidepools exposed to wave action.

Stypopodium flabelliforme

Kapoho Point, Kailua, Oahu, 2 feet

Common on sandy reefs in shallow water.  Blades are circular with torn margins.  Not calcified.

Turbinaria ornata

Makapu'u, Oahu

 

Makapu'u, Oahu

Black Point, Oahu

Abundant on surf-washed rocks in shallow water.


NORTHEAST PACIFIC

Fucus gardneri

Victoria, Canada

Victoria, Canada

ROCKWEED

Abundant on rocks in the intertidal and shallow subtidal.  Alaska to Central California.  Formerly known as Fucus distichus.

Macrocystis pyrifera

Long Point, Catalina, California, 20 feet

Long Point, Catalina, California, 20 feet

 

Rock Quarry, Catalina, California, 30 feet

GIANT PERENNIAL KELP

Abundant on rocky reefs.  Grows up to 14 inches per day.  Holdfast is pear-shaped and is the only part that survives during winter storms.  The most common large kelp south of Central California.  Alaska to Mexico; Peru to Chile; Tasmania & New Zealand.

Nereocystus luetkeana

Ogden Point, Victoria, Canada, 30 feet

Ogden Point, Victoria, Canada, 30 feet

BULL KELP

Abundant in nearshore waters, attached to hard surfaces including burrowing clams.  In extreme situations the singular stipe may attain a length of 118 feet.  Most common large kelp north of Central California to the Aleutian Islands.

 

 

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