Dichothrix Zanardini ex Bornet & Flahault, 1886

Holotype species: Dichothrix penicillata Zanardini ex Bornet & Flahault

Original publication and holotype designation: Bornet, É. & Flahault, C. (1886). Revision des Nostocacées hétérocystées contenues dans les principaux herbiers de France. Annales des Sciences Naturelles, Botanique, Septième série 3: 323-381.

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Description: Filamentous-thallose; filaments heteropolar, differentiated into basal and apical parts, obligately commonly falsely branched, solitary or in fasciculated colonies or strata; false branching lateral, always with only one branch, growing usually at first parallel with original trichome, later diverging. Trichomes and branches with branches with basal heterocytes, rarely develop intercalary heterocytes, solitary or (rarely) in twos; heterocytes usually heteropolar (unipored). Sheaths always present, usually firm, colorless or yellow-brown and lamellated, at the end joined to the trichome or widened and diverging. Trichomes with cylindrical or barrel-shaped cells, at the crosswalls constricted or unconstricted, hair-like narrowed to the apical ends; hairs are composed of a row of long, narrow, hyaline cells. Aerotopes and akinetes lacking. Division of cells perpendicular to the long axis of a trichome (sometimes meristematic zones), dissociation of trichomes at intercalary heterocytes before false branching. Reproduction by hormogonia, which separate from trichomes by help of necrotic cells after separation of the terminal hair. The majority of species live periphytically on stones or on aquatic plants in clear waterfalls, streams, on wet stony walls and in littorals of reservoirs. Several species are known from marine littoral.

Information contributed by: J. Komárek. The most recent alteration to this page was made on 2021-08-21 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 feminine.

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

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=43612

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 21 August 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 08 February 2023

 
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