Ascoseira Skottsberg, 1907
Holotype species: Ascoseira mirabilis Skottsberg
Original publication and holotype designation: Skottsberg, C. (1907). Zur Kenntnis der subantarktischen und antarktischen Meeresalgen. I. Phaeophyceen. In: Wissenschaftliche Ergebnisse der Schwedischen Südpolar-Expedition 1901-1903 unter Leitung von Dr. Otto Nordenskjöld. Vol. 4: 1, Part 6. ( Eds), pp. 1-172. Stockholm: Lithographisches Institut des Generalstabs.
Request PDFDescription: Thallus to 1.5 m long with a discoid holdfast, a short, flattened, dichotomously branching stipe and strap-shaped fronds, entire or divided from near the base into ligulate blades to 12 cm broad. Growth from an intercalary meristem at the base of the fronds. Thallus structure is parenchymatous and differentiated into an outer pigmented layer of small cells grading into a cortex of larger isodiametric cells and a medulla of longitudinally running filaments and aseptate "conducting channels" surrounded by hyphal filaments. Conducting channels contain densely packed physodes and are visible in the fronds as longitudinal dark threads. Discoid chloroplasts lack pyrenoids.
Life history is diplontic. Sexual reproduction is isogamous. Individuals are monoecious with conceptacles scattered all over the blades and containing chains of gametangia surrounding a central hair. Gametangia are eight-chambered and following the segregation of a vestigial nucleus, each chamber releases one gamete.
Gametes are heterokont, lack an eyespot and do not show phototaxis.
Information contributed by: M.N. Clayton. The most recent alteration to this page was made on 2014-06-20 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Silberfeld, T., Rousseau, F. & Reviers, B. de (2014). An updated classification of brown algae (Ochrophyta, Phaeophyceae). Cryptogamie Algologie 35(2): 117-156, 1 fig., 1 table.
Comments: Ascoseira grows subtidally and is endemic to the Antarctic Peninsula, South Shetland Islands, South Orkney Islands, South Georgia and South Sandwich Islands.
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Contributors
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera,
organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA)
and intended to be published in CD format.
These AlgaeBase descriptions are now being continually updated, and each current contributor is identified above.
The PSA and AlgaeBase warmly acknowledge the generosity of all past and present contributors and particularly the work of Dr Parker.
Descriptions of chrysophyte genera were subsequently published in J. Kristiansen & H.R. Preisig (eds.). 2001. Encyclopedia of Chrysophyte Genera. Bibliotheca Phycologica 110: 1-260.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=42683
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 20 June 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
