Stigonema C.ex & Flahault, 1886
Lectotype species: Stigonema mamillosum C.Agardh 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.
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.
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, -1130. Heidelberg: Springer Spektrum.
Description: Filamentous - thallose; thallus wooly or crusty, composed of free, coiled, true branched filaments, usually attached to the substrate, not diversified distinctly in basal filaments and branches. Trichomes bi- or multiseriate (only in young trichomes and at ends of branches uniseriate), sometimes very thick, irregularly laterally true branched (T- and V-type of branching), irregularly coiled, sometimes narrowed (with less number of cell rows) towards the ends, apical cell is sometimes larger than the other ones. Sheaths thin or thick, limited, later wide, lamellated and usually yellowish-brown; around cells in old parts of filaments sometimes special envelopes (trichomes disintegrating in separated cells within filaments). Cells barrel-shaped or roundly irregular, connected usually by one pore ("pit connections") one with another, which disappear in some segments of trichomes; cell content blue-green or olive-green, usually with prominent solitary granules. Heterocytes intercalary, solitary, rarely lateral, in a similar form as neighboring vegetative cells. Akinetes not known. Sometimes chroococcoid cell clusters arise. Cells divide in all planes, but the crosswise fission is mostly common in trichomes. Meristematic zones occur only in sections, in which hormogonia arise. Reproduction by hormogonia, which liberate from the ends of trichomes and branches, morphologically different from trichomes (more cylindrical, uniseriate); hormogonia two- or more-celled, rarely many-celled. Species occur in various biotopes all over the world, usually attached to the substrate or in soil, but not very common. More in tropical regions. Many species grow aerophytically or subaerophytically on bark of trees or wet rocks, from lowland to the alpine zone of high mountains (different species). Several species are known from pools, swamps and moors, where they grow in metaphyton or attached to stones and wood. Important are soil species in tropical habitats.
Information contributed by: J. Komárek. The most recent alteration to this page was made on 14 Jan 2014 by M.D. Guiry.
Numbers of names and species: There are 80 species names in the database at present, as well as 36 infraspecific names. Of the species names, 68 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: 11 April 2002 by M.D. Guiry
Verified by: 14 January 2014 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43623
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 26 October 2021.