Scytothamnus J.D.Hooker &, 1845
Holotype species: Scytothamnus australis (J.Agardh) J.D.Hooker & Harvey
Original publication and holotype designation: Hooker, J.D. & Harvey, W.H. (1845). Algae Novae Zelandiae; being a catalogue of all of the species of algae yet recorded as inhabiting the shores of New Zealand, with characters and brief descriptions of the new species discovered during the voyage of H.M. discovery ships "Erebus" and "Terror" and of others communicated to Sir W. Hooker by D. Sinclair, the Rev. Colenso, and M. Raoul. London Journal of Botany 4: 521-551.
Taxonomic status: currently recognized as a distinct genus.
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.
Description: Thallus terete, irregularly densely branched to 30 cm long and 3 mm diameter. Growth from a small group of apical cells. Thallus structure is parenchymatous and differentiated into a compact outer layer of small cells containing numerous physodes, a cortex of isodiametric cells cells and a medulla of loose filaments surrounded by mucilage. Stellate chloroplasts possess an axial pyrenoid penetrated by cytoplasmic channels. Phaeophycean hairs develop in cryptpostomata. Life history is haplodiplontic. Macrothalli are sporophytes producing ovoid to globose unilocular meiosporangia sunk amongst the surface layer of cells. Meiospores are heterokont, and develop into dioecious filamentous gametophytes. Sexual reproduction is isogamous. Plurilocular gametangia are multiseriate and form clusters. Gametes are heterokont, to 6 fm diameter and have an eyespot. Zygotes develop into diploid sporophytes. In culture, unfertilised gametes develop parthenogenetically and haploid macrothalli may develop directly on gametophytes. Scytothamnus grows intertidally in cold temperate and subantarctic regions of the southern hemisphere. It has also been recorded from the west coast of Canada. There is doubt over the most appropriate ordinal classification of Scytothamnus. Though classified in the Chordariales by Womersley (1987), I consider that the highly unusual chloroplast structure, the mode of growth and the presence of intercalary longitudinal divisions set Scytothamnus apart from this order. On the basis of these characters the affinities of Scytothamnus possibly lie with Splachnidium and Stereocladon. A possible third species recorded from the Falkland Islands requires further investigation.
Information contributed by: M. N. Clayton. The most recent alteration to this page was made on 19 Jun 2014 by M.D. Guiry.
Numbers of names and species: There are 4 species names in the database at present, of which 2 have been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..
Names: ('C' indicates a name that is 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):
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Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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.
Created: 28 December 2000 by M.D. Guiry
Verified by: 19 June 2014 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=42570
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 24 June 2019.