156,767 species and infraspecific names are in the database, 22,033 images, 60,595 bibliographic items, 449,807 distributional records.

Trichormus (Ralfs ex É.Bornet & C.Flahault) J.Komárek & K.Anagnostidis, 1989

Empire Prokaryota
Kingdom Eubacteria
Subkingdom Negibacteria
Phylum Cyanobacteria
Class Cyanophyceae
Subclass Nostocophycidae
Order Nostocales
Family Nostocaceae

Holotype species: Trichormus variabilis (Kützing ex Bornet & Flahault) Komárek & Anagnostidis

Original publication and holotype designation: Komárek, J. & Anagnostidis, K. (1989). Modern approach to the classification system of Cyanophytes 4 - Nostocales. Algological Studies 56: 247-345.

Taxonomic status: currently recognized as a distinct genus.

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.

Description: Filamentous-thallose; solitary filaments or (mainly) periphytic mats, clusters and strata, which are composed of Å coiled trichomes enveloped by colorless, fine or limited mucilage, without prominent sheaths; strata sometimes macroscopic. Trichomes uniseriate, isopolar, metameric, irregularly coiled, in later stages with several solitary, intercalary heterocytes which are usually situated in Å regular distances in the trichome from one another, mainly clearly constricted at the crosswalls, to the ends not attenuated, without any branching; end cells rounded or conical. Cells spherical, barrel-shaped or cylindrical, always without aerotopes. Heterocytes spherical, oval or cylindrical. Akinetes develop always apoheterocytic, i.e., they start to develop from vegetative cells in the middle between two heterocytes and later change all or almost all vegetative cells into akinetes, towards heterocytes. Cell division perpendicular to the long axis of a trichome. Reproduction by hormogonia, which separate from trichomes at heterocytes, and by the germination of akinetes. Dissociation of mats. Most species live in soil (incl. the type species), less are periphytic in littorals of different waters (important are species from rice fields, which are intense nitrogen fixers); few species are known from marine littorals. A couple of ecologically interesting species grow endophytically in intercellular spaces of Azolla or in roots of several Cycadaceae. Many species are known only from tropics, only few are distributed in temperate or subpolar zones.

Information contributed by: J. Komárek. The most recent alteration to this page was made on 4 Mar 2015 by M.D. Guiry.

Numbers of names and species: There are 44 species names in the database at present, of which 35 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.

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

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: 04 March 2015 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43088

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 November 2019.

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