Nizymenia Sonder, 1855
Holotype species: Nizymenia australis Sonder
Original publication and holotype designation: Sonder [O.G.] (1855 '1854'). [Plantae Muellerianae] Algae annis 1852 et 1853 collectae. Linnaea 26: 506-528.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Womersley, H.B.S. (1994). The marine benthic flora of southern Australia - Part IIIA - Bangiophyceae and Florideophyceae (Acrochaetiales, Nemaliales, Gelidiales, Hildenbrandiales and Gigartinales sensu lato). pp. 1-508, 167 figs, 4 pls, 4 maps. Canberra: Australian Biological Resources Study.
Description: Plants reach lengths of 20 cm, are erect from a discoid holdfast, and consist of linear flattened blades 1-2 mm wide irregularly branched to several orders from the margins. Central axial cells are often indistinct at the apices, and are usually so in older fronds, in which the rhizoids obscure them. Each axial cell gives rise to 4 periaxial cells. Carpogonial branches occur in small papillae formed on the blade surfaces. Each papilla encompasses a major filament on which 1 or 2 procarpic clusters originate from certain periaxial cells. Fertile periaxial cells in turn bear 3 branched filaments, 1 of them sterile, 2 of them bearing a 3 celled, outwardly oriented carpogonial branch. One of the two carpogonial filaments also produces a lateral filament in which the hyperbasal cell is enlarged and presumably functions as the auxiliary cell. Diploidization of the auxiliary cell has not been observed, but presumably involves a short connecting filament. Cystocarps are as described for the family; carposporangia occur in chains of 4. Tetraspsorangia are as for the family; spermatangia are unknown. The carposporophyte development of the genus was documented by Searles (1968), and the tetrasporangial features described by Womersley (1971a).
Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 7 Oct 2010 by M.D. Guiry.
Comments: Distribution: Frequent in drift and from shallow subtidal to over 20 m depths from South Australia to Victoria, and around Tasmania. The Nizymeniaceae is a family of 2 genera and 3 species, all endemic to southern Australia. Plants are cartilaginous, erect from discoid holdfasts, and are uniaxial, with 3-4 periaxial cells borne per central axial cell. The medulla is largely filamentous due to extensive growth of descending rhizoidal filaments from inner cells of the cortical fascicles, and the cortex is pseudoparanchymatous. Cortical rhizoids have thick walls and narrow lumens similar to the "rhizines" characteristic of the Gelidiaceae. Inner cells are multinucleate and connected by secondary pit connections. Female gametophytes are procarpic and usually polycarpogonial, the carpogonial branches forming on one or more of three filaments extending in a cluster from the thallus margin, with one of the filaments containing an intercalary auxiliary cell. The carpogonial branches are 3-celled and oriented outwardly. Following fertilization the carpogonium emits a single connecting filament, which fuses to the adjacent auxiliary cell and results in a single gonimoblast initial directed toward the thallus surface. Carposporophytes consist of gonimoblast filaments that radiate thallus-outwardly from a basal fusion cell; carposporangia form in terminal chains and are encased in an externally protruding, ostiolate pericarp. Spermatangia are formed in clusters on the upper cells of uniseriate, branched filaments that grow from surface cortical cells in localized tufts. Tetrasporangia are likewise borne on uniseriate filaments, being cruciate and sessile on the distal cells of the tufts. Tetrasporophytes and gametophytes are isomorphic.
Numbers of names and species: There are 3 species names in the database at present, of which 3 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
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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: 01 January 2001 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=35059
Please cite this record as:
Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 January 2019.