Ulvaria Ruprecht, 1850
Lectotype species: Ulva fusca Postels & Ruprecht
Currently accepted name for the type species: Ulvaria fusca (Wittrock) Vinogradova
Original publication: Ruprecht, F.J. (1850). Algae ochotenses. Die ersten sicheren Nachrichten über die Tange des Ochotskischen Meeres. pp. 1-243, 10 pls. St. Petersburg: Buchdruckerei der Kaiserlichen Akademie der Wissenschaften.
Type designated in: Papenfuss, G.F. (1960). On the genera of the Ulvales and the status of the order. Journal of the Linnean Society of London, Botany 56: 303-318, 21 figs, 6 pls.
Description: Thallus at first a hollow, club-shaped sac with walls one cell thick. Saccate thallus ruptures by degeneration and tearing of apical end. Mature thallus funnel-shaped or expanded monostromatic blade, attached to substrate by a peltate holdfast or split to base, obscuring original location of holdfast. Rhizoidal holdfast and area of blade surrounding holdfast with rhizoids along upper surface. Blades to 30 cm or more in length, and from 15 to 75 um or more in thickness, thinnest at the margins. Rhizoidal zone to 100 um or more in thickness. Cells in surface view closely arranged, angular, irregular and mostly unordered; generally between 9 and 30 um across. Cells in sectional view nearly isodiametric to elongated perpendicular to the blade surface. Single parietal chloroplast, concentrated on ends of cells adjacent to thallus surfaces; reticulate in between ends; 1 to 6 pyrenoids. Cells of blade uninucleate. Life history an alternation of isomorphic, unisexual haploid gametophytes and diploid sporophyte. Meiosis occurs during sporogenesis; haploid chromosome number is 9. Asexual reproduction by quadriflagellated ovoid zoospores; sexual reproduction by biflagellated ovoid gametes of similar size. Swarmers released one at a time through a pore with a raised rim. Gametes positively phototactic; zoospores initially positively phototactic, later becoming negatively phototactic. Reproductive cells germinate into uniseriate filaments attached by a basal rhizoidal cell. Germlings later become pluriseriate by repeated longitudinal cell divisions perpendicular to the surface of the filament. Separation of cells along the longitudinal axis leads to the development of a clavate, saccate germling with walls one cell thick. Rhizoids develop from inner surfaces of basals cells Degeneration of apical end of saccate germling results in peltate monostromatic thallus. Cosmopolitan in temperate waters of the northern hemisphere; subtidal and intertidal zones on stones, shell, algae and other hard substrates.
Information contributed by: C. Tanner & M.D. Guiry. The most recent alteration to this page was made on 2010-09-23 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Brodie, J., Maggs, C.A. & John, D.M. (2007). Green seaweeds of Britain and Ireland. pp. [i-v], vi-xii, 1-242, 101 figs. London: British Phycological Society.
Comments: In the past several species have been included in the genus Ulvaria. Of these one, U. oxysperma, has been shown to have closer affinities to the Ulotrichales and has been placed in the genus Gayralia. Two other species, U. fusca and U. splendens fit with the range of morphological variation described for U. obscura. Dube (1967) has examined the life history of Ulvaria fusca var. blyttii.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=37495
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 23 September 2010. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 December 2022