Vaucheria A.P.de Candolle, 1801: 20

Classification:
Empire Eukaryota
Kingdom Chromista
Subkingdom Chromobiota
Infrakingdom Heterokonta
Phylum Heterokontophycophyta
Class Xanthophyceae
Order Vaucheriales
Family Vaucheriaceae

Holotype species: Vaucheria disperma A.P.de Candolle

Original publication and holotype designation: Candolle, A.P. de (1801). Extrait d'un rapport sur les conferves. Bulletin des Sciences, par la Société Philomathique de Paris 3: 17-21.

Taxonomic status: currently recognized as a distinct genus.

Gender: This genus name is currently treated as feminine.

Description: The only genus of its family, consisting of decumbent or cushion-like mats of interwoven, grass- to dark-green, sparingly-branched siphons 10-200 &m in diam., with indeterminate apical growth and lateral branching, sometimes with colorless rhizoidal siphons. Parietal cytoplasm contains many discoid chloroplasts (Å pyrenoid) and small nuclei, surrounding a central large vacuole. Nuclear envelope remains intact during mitosis, surrounding spindle apparatus. Freshwater species often infected by galls, producing large outgrowths from siphon. Asexual reproduction by terminal, clavate aplanosporangia; multinucleate zoosporangia with numerous pairs of only slightly unequal flagella; or thick-walled akinetes formed by septa in siphon. Sexual reproduction oogamous, the oogonia bearing single eggs and male gametangia producing several heterokontan sperm. Gametangia, also isolated by septa, are arranged in either regular bisexual groups or loose arrangements of one or more oogonia and/or male gametangia on monoecious or dioecious plants. Male gametangia usually tubular, 10-700 &m long, curved or straight, usually releasing sperm through one or more pores. Oogonium 30-400 &m in diam., initially multinucleate; uninucleate before fertilization (usually) through pore in oogonial wall. Germination of oospore (zygote) by means of dehiscence at predetermined location, presumably after meiosis. Vaucheria is widespread in fresh to saline water, every continent (including Antarctica); submergent, amphibious, semi-emergent or terrestrial; intertidal to sublittoral, on mudflats, mangroves, saltmarsh, estuaries, streams, channels, farmland, lake and pond fringes, and almost any wetland. Acts as stabilizer of exposed mud; able to tolerate aerial desiccation due to buried siphons which grow through deposited silt. Sometimes encrusted in calcium carbonate. Periodicity and distribution of saltmarsh species depends on salinity and soil-moisture. Physiological studies include role of light on branch formation, movement of chloroplasts, winding of mitochondrial filaments, response of vegetative growth and reproduction to salinity, and phototrophic control of vegetative growth and zoosporogenesis. Culture requirements have been extensively studied. Peroxisomes in marine and freshwater species with similar enzymic equipment to those of other Tribophyceae but distinct form all other algae. Sections distinguished mainly on disposition and morphology of male gametangia; species delineated using morphology of antheridia, oogonia and oospores, and arrangement of gametangia. Observed variation of these features in culture has led to some reduction in number of species. Pseudovaucheria spongeliae Lami is an endozoic, marine, siphonous alga whose taxonomic placement is uncertain, but is probably synonymous with Vaucheria.

NCBI Nucleotide Sequences

Numbers of names and species: There are 259 species (and infraspecific) names in the database at present, of which 71 have 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):

Information contributed by: T. J. Entwisle. The most recent alteration to this page was made on 25 Apr 2010 by M.D. Guiry.

Contributors
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.