Ascoseira, 1907: 148
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. ( Eds) Vol. 4: 1, pp. 1-172. Stockholm: Lithographisches Institut des Generalstabs.
Taxonomic status: currently recognized as a distinct genus.
Description: 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.
Comments: Ascoseira grows subtidally and is endemic to the Antarctic Peninsula, South Shetland Islands, South Orkney Islands, South Georgia and South Sandwich Islands.
NCBI Nucleotide Sequences
Numbers of names and species: There is only one species or infraspecific name in the database at present, which has been flagged as currently accepted taxonomically.
Names: ('C' indicates a name that is currently accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
Ascoseira mirabilis Skottsberg C - type
Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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: http://www.algaebase.org/search/genus/detail/?genus_id=42683
Cite this record as:
Guiry, M.D. & Guiry, G.M. 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 12 March 2014.
Algaebase taxon LSID: urn:lsid:algaebase.org:taxname:7549