Staurastrum Meyen ex, 1848
Lectotype species: Staurastrum paradoxum Meyen ex Ralfs
Original publication:Ralfs, J. (1848). The British Desmidieae. pp. [i]-xxii, [i], -226, pls I-XXXV. London: Reeve, Benham & Reeve.
Type designated in Guiry, M.D. (2013). Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae). Algae. An International Journal of Algal Research 28: 1-29.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Guiry, M.D. (2013). Taxonomy and nomenclature of the Conjugatophyceae (=Zygnematophyceae). Algae. An International Journal of Algal Research 28: 1-29.
Description: Cells small to large, 2- to 12-radiate in end view, with shallow or deep median constriction (isthmus) where semicell walls overlap, and two intergrading cell morphologies. Most species with long, hollow processes on each semicell (number related to radiation pattern); processes usually with two or more terminal spinules, and possibly one or more series of denticulations, spines or verrucae along process and on apex and body of central axis of semicell. On other species, semicell angles rounded, truncate or with short processes; cell wall smooth or with rows of small granules or spinules. Chloroplasts usually one per semicell, stellate (lobed) in end view, with axial pyrenoid or with several pyrenoids in lobes extending into cell angles or processes. Nucleus in isthmus. Asexual reproduction by cell division and new semicell formation typical of Cosmarium-type desmids (see Cosmarium). Sexual reproduction by conjugation known for many species. Gametangia come together within broad gelatinous envelope; gametangia fuse in conjugation tube. Mature zygospores usually spherical, with long furcate spines. Many species cosmopolitan; others restricted to tropical areas or certain continents. Species with long processes often planktonic. Most species bethic or periphytic in acidic, oligotrophic lakes, ponds and swamps. Proposals to segregate groups of species into distinct genera generally ignored because of difficulty in establishing clear generic limits. Former Staurastrum taxa with single spine (or thickened cell wall) at each angle now referred to Staurodesmus. Palamar-Mordvintseva (1976) segregated species without long processes into several genera; not generally accepted except in Russian and Ukrainian publications. Cylindriastrum includes species with elongate angular- cylindric cells. Cosmoastrum includres species with smooth wall or with rows of granules or spinules over entire wall or only around cell angles. Raphidiastrum includes species with two or more spines at each angle and those with a single angular spine which also have rows of granules or spinules on cell wall. Placement of some taxa arbitrary since these genera have intergrading forms.
Information contributed by: J.F. Gerrath. The most recent alteration to this page was made on 12 Sep 2013 by M.D. Guiry.
Numbers of names and species: There are 1173 species names in the database at present, as well as 2352 infraspecific names. Of the species names, 674 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.
Hall, J.D., Karol, K.G., McCourt, R.M. & Delwiche, C.F. (2008). Phylogeny of the conjugating green algae based on chloroplast and mitochondrial nucleotide sequence data. Journal of Phycology 44: 467-477.
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: 12 September 2013 by M.D. Guiry
Linking to this page: http://algaebase.org/search/genus/detail/?genus_id=43546
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 30 October 2020.