Flattened acid kelp • Desmarestia ligulata*
Centre and Right: photos by Thalia Christou and Julie Mundy. Left: specimen collection number PTM 447 in the UBC Herbarium Algae Database. Images courtesy of Sandra Lindstrom. Search the collection number in the database for further details on this specimen, or search this species for additional occurrences.
Identification
This somewhat fern-like annual brown alga is flattened and ligulate (strap-like), and varies from golden brown to olive brown. The blade has several orders of alternate branching; the main axis of the blade gets to 2 cm wide and other branches are narrower (defined by some researchers as less than 1 cm wide). The main axis has a midrib, and the branches have lateral veins. Flattened acid kelp can get to 80 cm long, though it is usually much shorter.
* Note: there is uncertainty regarding the distinctions between some Desmarestia species, including D. latissima, D. ligulata, and D. munda. Currently all three are accepted species, however more work needs to be done to determine if any of these species or others in the genus are morphological variations of the same species. Gabrielson et al. describe D. ligulata as having more than two orders of branching and branches measuring less than 1 cm wide, whereas D. latissima has one or two orders of branching and branches measuring more than 1 cm wide. Other sources distinguish D. ligulata and D. munda on similar grounds, with the latter having wider branches than the former, and branches at least as wide as the main axis.
Habitat & Range
Flattened acid kelp grows in the very low intertidal and subtidal of semi-exposed to semi-protected shorelines. It is reported from Mexico to Unalaksa Island, Alaska in the eastern Pacific and from Korea to Russia in the western Pacific. It is also reported in some parts of the Atlantic and other oceans around the world, though there is evidence that differences exist between these populations at the molecular level.
Intriguing Info
As with some other Desmarestia species, flattened acid kelp has a high acid content which results in damage to nearby species as well as its own tissues; this also means that specimens break down rapidly.
iNaturalist
https://www.inaturalist.org/taxa/328357-Desmarestia-ligulata
This somewhat fern-like annual brown alga is flattened and ligulate (strap-like), and varies from golden brown to olive brown. The blade has several orders of alternate branching; the main axis of the blade gets to 2 cm wide and other branches are narrower (defined by some researchers as less than 1 cm wide). The main axis has a midrib, and the branches have lateral veins. Flattened acid kelp can get to 80 cm long, though it is usually much shorter.
* Note: there is uncertainty regarding the distinctions between some Desmarestia species, including D. latissima, D. ligulata, and D. munda. Currently all three are accepted species, however more work needs to be done to determine if any of these species or others in the genus are morphological variations of the same species. Gabrielson et al. describe D. ligulata as having more than two orders of branching and branches measuring less than 1 cm wide, whereas D. latissima has one or two orders of branching and branches measuring more than 1 cm wide. Other sources distinguish D. ligulata and D. munda on similar grounds, with the latter having wider branches than the former, and branches at least as wide as the main axis.
Habitat & Range
Flattened acid kelp grows in the very low intertidal and subtidal of semi-exposed to semi-protected shorelines. It is reported from Mexico to Unalaksa Island, Alaska in the eastern Pacific and from Korea to Russia in the western Pacific. It is also reported in some parts of the Atlantic and other oceans around the world, though there is evidence that differences exist between these populations at the molecular level.
Intriguing Info
As with some other Desmarestia species, flattened acid kelp has a high acid content which results in damage to nearby species as well as its own tissues; this also means that specimens break down rapidly.
iNaturalist
https://www.inaturalist.org/taxa/328357-Desmarestia-ligulata
References
Guiry, M.D. & Guiry, G.M. 2014. Desmarestia ligulata (Stackhouse) J.V.Lamouroux. National University of Ireland, Galway. Accessed 26/11/2014.
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). Desmarestia ligulata Seaweeds of Alaska. Accessed 26/11/2014.
O'Clair, R. and Lindstrom, S. Desmarestia ligulata (Lightfoot) Lamouroux. 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 26/11/2014.
Authors and editors of page
Kelly Fretwell, and Brian Starzomski (2014).
Guiry, M.D. & Guiry, G.M. 2014. Desmarestia ligulata (Stackhouse) J.V.Lamouroux. National University of Ireland, Galway. Accessed 26/11/2014.
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). Desmarestia ligulata Seaweeds of Alaska. Accessed 26/11/2014.
O'Clair, R. and Lindstrom, S. Desmarestia ligulata (Lightfoot) Lamouroux. 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 26/11/2014.
Authors and editors of page
Kelly Fretwell, and Brian Starzomski (2014).