Stigonema C.Agardh ex Bornet & 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.
Request PDFType 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.
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 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 neuter.
Most recent taxonomic treatment adopted: Strunecký, O., Ivanova, A.P. & Mares, J. (2022 '2023'). An updated classification of cyanobacterial orders and families based on phylogenomic and polyphasic analysis (Review). Journal of Phycology 59(1): 12-51.
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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=43623
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 06 March 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
