Sea brush • Odonthalia floccosa
{Odonthalia = toothed branch}
Left image: specimen collection number SCL 15350 in the UBC Herbarium Algae Database. Search the specimen collection number in the database for further information, or search the species for more information. Right photo by Jenn Burt.
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Identification
Sea brush is a highly-branched perennial red seaweed. It varies in colour from dark red to brownish-black, though branch tips may bleach light brown. Branching is alternate and distichous (occurring in one plane, i.e. giving the seaweed a flattened appearance), and branches are round or somewhat flattened in cross-section. The tertiary branches (last order) bear clusters of small and pointed branchlets, giving branch tips a tufted look. Sea brush has a disc-shaped holdfast, forms dense mats, and reaches 40 cm tall. See more photos on the AlgaeBase species page.
Habitat & Range
Sea brush grows on rock in the low intertidal. It is common along semi-exposed and semi-protected shorelines, with moderate currents or surf. Its range extends from the Bering Sea and Aleutian Islands to southern California.
Similar Species
Black pine (Neorhodomela larix) and Oregon pine (N. oregona) are also dark tufted-looking red seaweeds. The former gets this appearance from clusters of small branchlets along the whole length of the main branches, which are unbranched or only branch a few times. The latter is more branched but still has clusters of branchlets along the length of its main axis, rather than at the ends as with sea brush. The Pacific Northwest is home to a few other Odonthalia species as well.
Intriguing Info
Sea brush frequently hosts epiphytic algae such as sea cauliflower (Leathesia marina) and Soranthera ulvoidea. Dense mats of sea brush tend to house zooplankton as well.
iNaturalist
https://www.inaturalist.org/taxa/322180-Odonthalia-floccosa
Sea brush is a highly-branched perennial red seaweed. It varies in colour from dark red to brownish-black, though branch tips may bleach light brown. Branching is alternate and distichous (occurring in one plane, i.e. giving the seaweed a flattened appearance), and branches are round or somewhat flattened in cross-section. The tertiary branches (last order) bear clusters of small and pointed branchlets, giving branch tips a tufted look. Sea brush has a disc-shaped holdfast, forms dense mats, and reaches 40 cm tall. See more photos on the AlgaeBase species page.
Habitat & Range
Sea brush grows on rock in the low intertidal. It is common along semi-exposed and semi-protected shorelines, with moderate currents or surf. Its range extends from the Bering Sea and Aleutian Islands to southern California.
Similar Species
Black pine (Neorhodomela larix) and Oregon pine (N. oregona) are also dark tufted-looking red seaweeds. The former gets this appearance from clusters of small branchlets along the whole length of the main branches, which are unbranched or only branch a few times. The latter is more branched but still has clusters of branchlets along the length of its main axis, rather than at the ends as with sea brush. The Pacific Northwest is home to a few other Odonthalia species as well.
Intriguing Info
Sea brush frequently hosts epiphytic algae such as sea cauliflower (Leathesia marina) and Soranthera ulvoidea. Dense mats of sea brush tend to house zooplankton as well.
iNaturalist
https://www.inaturalist.org/taxa/322180-Odonthalia-floccosa
References
Lamb, A., and Hanby, B. (2005). Marine Life of the Pacific Northwest [electronic version]. Madeira Park, BC: Harbour Publishing.
Lindberg, M. and Lindstrom, S. (2010). Odonthalia floccosa Sea Brush. Seaweeds of Alaska. Accessed 15/09/2015.
Druehl, L. 2000. Pacific Seaweeds: A guide to common seaweeds of the west coast. Harbour Publishing: Madeira Park, BC, Canada. Pp. 123-124.
O'Clair, R. and Lindsrom, S. Odonthalia floccosa (Esper) Falkenberg. In Klinkenberg, Brian. (Ed.). E-Flora BC: Electronic Atlas of the Plants of British Columbia. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. Accessed 15/09/2015.
Authors and editors of page
Kelly Fretwell and Brian Starzomski (2015).
Lamb, A., and Hanby, B. (2005). Marine Life of the Pacific Northwest [electronic version]. Madeira Park, BC: Harbour Publishing.
Lindberg, M. and Lindstrom, S. (2010). Odonthalia floccosa Sea Brush. Seaweeds of Alaska. Accessed 15/09/2015.
Druehl, L. 2000. Pacific Seaweeds: A guide to common seaweeds of the west coast. Harbour Publishing: Madeira Park, BC, Canada. Pp. 123-124.
O'Clair, R. and Lindsrom, S. Odonthalia floccosa (Esper) Falkenberg. In Klinkenberg, Brian. (Ed.). E-Flora BC: Electronic Atlas of the Plants of British Columbia. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. Accessed 15/09/2015.
Authors and editors of page
Kelly Fretwell and Brian Starzomski (2015).