Mychodea J.D.Hooker &, 1847
Lectotype species: Mychodea carnosa J.D.Hooker & Harvey
Original publication:Hooker, J.D. & Harvey, W.H. (1847). Algae tasmanicae: being a catalogue of the species of algae collected on the shores of Tasmania by Ronald Gunn, Esq., Dr. Heannerett, Mrs. Smith, Dr. Lyall and Dr. J.D. Hooker; with characters of the new species. London Journal of Botany 6: 397-417.
Type designated in Schmitz, F. (1889). Systematische Übersicht der bisher bekannten Gattungen der Florideen. Flora oder Allgemeine botanische Zeitung 72: 435-456, pl. XXI.
Taxonomic status: currently recognized as a distinct genus.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Kraft, G.T. & Saunders, G.W. (2017). Mychodea and the Mychodeaceae (Gigartinales, Rhodophyta) revisited: molecular analyses shed light on interspecies relationships in Australia's largest endemic genus and family. Australian Systematic Botany 30: 230-258, 16 figs.
Description: Plants are erect from a discoid or stoloniferous base, cartilaginous in texture, and range from terete and radially branched through compressed to broadly flattened with marginal or submarginal branching. Apices are uniaxial, the structure obscure in some of the flattened species, with each central axial cell giving rise to two periaxial derivatives as well as, in lower portions of the fronds, distinctive adventitious cells or short chains of cells that bridge the junction between and link adjacent central axial cells. The cross sections of many species are distinctive in having a complex medulla in which the central axial filament is immediately surrounded by narrow rhizoidal filaments, then by a layer of large isodiametric cells that give a polysiphonous appearance to the section, then by progressively smaller outer medullary and cortical layers. Inner cells and rhizoidal filaments have abundant secondary pit connections, and all but surface cells are multinucleate. Gametophytes are monoecious, polycarpogonial and procarpic, the supporting cells differentiating in the inner cortex and bearing varying numbers of 3-celled carpogonial branches directed toward the thallus surface. Fusion of a fertilized carpogonium with the bearing supporting cell converts the latter to an auxiliary cell, which emits multiple filamentous gonimoblasts towards the thallus interior. Gonimoblasts ramify among interior gametophytic tissues, fuse or secondarily pit-connect to it at numerous points, and give rise to isolaterd clusters of branched chains of carposporangia directly, or indirectly from gametophytic cells that appear to have been diploidized, often after no visible direct contact with gonimoblasts. Cystocarps are either embedded or protuberant, in the latter case being surrounded by a pericarp but in all events without a surrounding hull of modified gametophytic filaments. Ostioles are absent. Spermatangia occur in isolated clusters in which several mother cells surround a single bearing cell. Tetrasporophytes are isomorphic with gametophytes, the tetrasporangia being either terminal or intercalary in the outer cortex and zonately divided.
Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 27 Nov 2017 by M.D. Guiry.
Characters considered diagnostic of Mychodea: The genus has the characteristics of the family, the species being distinguished on such features as branching pattern, degree of compression or flattening, degree of differentiation of medullary cell types, type of anchorage, position of cystocarps, and the site and disposition of the tetrasporangia. Plants of the largest species reach 40 cm in length. A full account of the generic features is given by Kraft & Saunders (2017: 231).
Comments: The genus has been monographed by Kraft (1978) and Kraft & Saunders (2017). Kraft (1978) considers Mychodea to be a probable offshoot of the Areschougiaceae/Cystocloniaceae line of development and to constitute one of the most specialized of the gigartinalean families.
Distribution: Endemic to the southern half of Australia, most species occurring on rock or as seagrass epiphytes from shallow subtidal habitats to over 20 m depths. The Mychodeaceae is a family of one genus and 21 species, with Mychodea being the largest wholly endemic genus of marine algae in Australia.
Numbers of names and species: There are 38 species names in the database at present, of which 20 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):
Click here to also show infraspecific names in the list below.
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: 27 November 2017 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=35048
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 19 April 2019.