156,011 species and infraspecific names are in the database, 21,990 images, 60,295 bibliographic items, 442,406 distributional records.

Hassallia Berkeley ex Bornet & Flahault, 1886

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

Lectotype species: Hassallia byssoidea Hassall ex Bornet & Flahault

Original publication:Bornet, É. & Flahault, C. (1886 '1887'). Revision des Nostocacées hétérocystées contenues dans les principaux herbiers de France (Troisième fragment). Annales des Sciences Naturelles, Botanique, Septième série 5: 51-129.
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Type designated in Geitler, L. (1942). Schizophyta: Klasse Schizophyceae. In: Die natürlichen Pflanzenfamilien, Sweite Auflage. (Engler, A. & Prantl, K. Eds) Vol.1b, pp. 1-232. Leipzig: Wilhelm Engelmann.

Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Komárek, J. (2013). Süsswasserflora von Mitteleuropa. Cyanoprokaryota: 3rd part: heterocystous genera. Vol. 19 pp. [i]-xviii, [1]-1130. Heidelberg: Springer Spektrum.

Description: Filamentous; filaments heteropolar, with basal parts with heterocytes and free apical ends, commonly falsely branched with solitary lateral branches initiating at the heterocytes (mainly unipored) and fragile (sometimes liberating from the "mother" filament), united in fasciculate, caespitose, crustose, thin or woolly mats, sometimes creeping on a substrate; branches diverging from the main trichome, more or less short, usually arcuated. Sheaths thick, firm, lamellated, colorless or yellow-brown, open at the apex. Trichomes and branches with basal (rarely also with intercalary) heterocytes, cylindrical, not attenuated or slightly attenuated at apices, constricted at the crosswalls. Cells barrel-shaped, shorter than wide to discoid; end cells slightly narrowed and widely rounded, with granular content. Aerotopes and akinetes lacking. Cells divide crosswise to the trichome axis, characteristic are the terminal meristematic zones. Reproduction by separated branches or hormogonia, which germinate at both sides, but later (after formation of heterocytes) they change in heteropolar growth. Most species are aerophytic, growing on stones and bark of trees, several species occur rarely in submersed biotopes. Distribution of various species is poorly known, mainly because of many misidentifications.

Information contributed by: J. Komárek. The most recent alteration to this page was made on 30 Mar 2017 by M.D. Guiry.

Numbers of names and species: There are 24 species names in the database at present, as well as 5 infraspecific names. Of the species names, 16 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: 23 April 2002 by M.D. Guiry

Verified by: 13 January 2014 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44303

Citing AlgaeBase
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 18 August 2019.

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