Onkonema Geitler, 1933

Holotype species: Onkonema compactum Geitler

Original publication and holotype designation: Geitler, L. (1933). Diagnosen neuer Blaualgen von den Sunda-Inseln. Arch. Hydrobiol. Suppl. 12: 622-634.

Description: Unicellular-colonial-pseudofilamentous; thallus microscopic, irregular, periphytic, creeping on the substrate, with cells arranged into flat or 3 -dimensional groups (chroococcacean stages), short, irregular rows, enveloped by thin, firm, but confluent sheaths, to pseudofilaments with irregular branching; rows of cells uni- to bi- or multiseriate, mainly with the apical growth (= prevailing division of "terminal" cells). Cells irregular, in rows and especially at their ends elongated or more or less cylindrical, slight narrowed and rounded. Cells divide irregularly in different planes, in rows mostly perpendicular to the growth direction; sometimes successive division in several smaller cells (nanocytes), which liberate from thallus and serve to the reproduction. The type species grows periphytic (epiphytic on other algae and cyanophytes) in warm and thermal springs in tropical countries (Indonesia - Java, Zambia).

Information contributed by: J. Komárek. The most recent alteration to this page was made on 2023-03-03 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.

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

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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=44908

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 03 March 2023. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 04 May 2024