Trichormus (Ralfs ex Bornet & Flahault) Komárek & Anagnostidis, 1989

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.

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 2023-03-06 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 masculine.

Most recent taxonomic treatment adopted: Strunecky, O., Ivanova, A.P. & Mares, J. (2023). An updated classification of cyanobacterial orders and families based on phylogenomic and polyphasic analysis (Review). Journal of Phycology 59(1): [1-40] 12-51.

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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.

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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 06 March 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 28 May 2023

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