153,615 species and infraspecific names are in the database, 20,981 images, 59,407 bibliographic items, 412,628 distributional records.

Rivularia C.Agardh ex Bornet & Flahault, 1886

Classification:
Empire Prokaryota
Kingdom Eubacteria
Subkingdom Negibacteria
Phylum Cyanobacteria
Class Cyanophyceae
Subclass Nostocophycidae
Order Nostocales
Family Rivulariaceae

Lectotype species: Rivularia atra Roth ex Bornet & Flahault

Original publication:Bornet, E. & Flahault, C. (1886 '1887'). Revision des Nostocacées hétérocystées contenues dans les principaux herbiers de France (deuxième fragment). Annales des Sciences Naturelles, Botanique, Septième Série 4: 343-373.
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Type designated in Gardner, N.L. (1932). The Myxophyceae of Porto Rico and the Virgin Islands. In: Scientific Survey of Porto Rico and the Virgin Islands. Volume VIII. Part 2. (Anon. Eds), pp. 249-311. New York: New York Academy of Sciences.
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Taxonomic status: currently recognized as a distinct genus.

Gender: This genus name is currently treated as feminine.

Most recent taxonomic treatment adopted: Komárek, J., Kastovsky, J., Mares, J. & Johansen, J.R. (2014). Taxonomic classification of cyanoprokaryotes (cyanobacterial genera) 2014, using a polyphasic approach. Preslia 86: 295-335.

Nomenclatural notes
The ING entry (14 Oct 2018) is "Rivularia C. A. Agardh ex É. Bornet et C. Flahault, Ann. Sci. Nat. Bot. ser. 7. 3: 341; 4: 345. 1 Jan 1886 (non A. W. Roth 1797). LT.: R. dura Roth ex Bornet et Flahault (vide L. Geitler in A. Engler et K. Prantl, Nat. Pflanzenfam. ed. 2. 1b: 169. 1942) CYANOPHYCEAE [NOST. HET.]-RIVULARIACEAE (2) 9 Feb 1996." However, Gardner (1932: 307, "Type species, Rivularia atra.") provided an earlier typification. - (14 Oct 2018) - M.D. Guiry

Description: Filamentous; filaments heteropolar, differentiated into basal and apical parts, simple, joined parallel into firm, at the beginning of the vegetation cycle hemispherical or spherical, later sometimes vast, flat, macroscopic, irregular strata, to several cm or dm in diam. and several mm thick; strata layered (sometimes with several layers), with densely agglomerated trichomes, oriented by their bases with heterocytes to the substrate and by the apical hair-like parts to the surface of the colony. Strata gelatinous to leathery or intensely incrusted by calcium carbonate, always covering the substrate. Trichomes more or less cylindrical, constricted or unconstricted at the cross walls, dividing at intercalary heterocytes: the divided trichomes separate from one another, but remain parallel located within the mother sheaths in the colony. Hairs composed of narrow, long, hyaline cells. Sheaths firm, sometimes lamellated, colorless or yellow-brown, enveloping all the "daughter" trichomes, which produce their own sheaths. Aerotopes and akinetes lacking. Cell division perpendicular to the long axis of a trichome, later in meristematic zones. Reproduction by dissociation of trichomes within colonies and heterocytes and by hormogonia, separating after the separation of the hair by the help of necridic cells and sometimes liberating from the colonies. Only periphytic species, often on calcareous substrates (and then intensely incrusted by calcium carbonate), but exist also epilithic and epiphytic, not encrusted species. Important members of travertine-forming biocenoses. Several species known from marine littoral; in fresh waters, they prefer clear, unpolluted, streaming or stagnant waters.

Information contributed by: J. Komárek. The most recent alteration to this page was made on 14 Oct 2018 by M.D. Guiry.

Numbers of names and species: There are 96 species names in the database at present, as well as 12 infraspecific names. Of the species names, 50 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.

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Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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.

Created: 28 December 2000 by M.D. Guiry

Verified by: 14 October 2018 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=42977

Citing AlgaeBase
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 19 November 2018.

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