157,562 species and infraspecific names are in the database, 22,210 images, 60,980 bibliographic items, 458,858 distributional records.

Roya West & G.S.West, 1896

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Viridiplantae
Infrakingdom Streptophyta infrakingdom
Phylum Charophyta
Class Zygnematophyceae
Subclass Zygnematophycidae
Order Zygnematales
Family Mesotaeniaceae

Holotype species: Roya obtusa (Brébisson) West & G.S.West

Original publication and holotype designation: West, W. & West, G.S. (1896). On some new and interesting freshwater algae. Journal of the Royal Microscopical Society 16: 149-165, 2 pls.
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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.

Taxonomic notes
Suborder Zygnematiinae, family Mesotaeniaceae (Brook & Johnson in John et al. 2002). However, they note that Roya and Tortitaenia possess features linking them to certain placoderm desmids of the suborder Desmidiineae. - (21 Jun 2012) - Wendy Guiry

Taxonomic placement diffiicult. "Placement of Roya spp., which may or may not be part of the Gonatozygaceae (Gontcharov et al. 2004), remains unclear, but they are supported as members of a lineage including most Desmidiales."(Hall et al. 2008: 471). - (21 Jun 2012) - Wendy Guiry

Description: Cells solitary, small to medium sized (22-195 µm), elongate-cylindric (length 4-60 times width), slightly curved or straight, with broadly rounded or truncate ends. Chloroplast an axial ribbon with row of up to 12 pyrenoids; cells with two chloroplast observed. Nucleus parietal at middle of cell (often in median notch in chloroplast), or between chloroplasts, if two present. Ultrastructure of cell wall two layered. Asexual reproduction only by transverse cell division. Sexual reproduction by conjugation known for 2 species; homothallic, without conjugation tube in R. obtusa. Naked gametes exite gametangia through pore at tip of short papilla. Zygotes form midway between gametangia; mature zygospores spherical, smooth-walled. Gamete nuclei remain distinct in dormant zygospore; karyogamy possibly at germination, similar to Netrium. Zygospore germination, however, not observed.

Information contributed by: J.F. Gerrath. The most recent alteration to this page was made on 12 Jul 2018 by M.D. Guiry.

Comments: Roya usually in low numbers in oligotrophic, aquatic habitats or in Sphagnum bogs in Europe, Soviet Union, North America and South America; occasional records from subaerial habitats (on wet rocks or among mosses) in alpine environments.

Numbers of names and species: There are 6 species names in the database at present, as well as 6 infraspecific names. Of the species names, 6 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.

References
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.

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.

Created: 11 April 2002 by M.D. Guiry

Verified by: 12 July 2018 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=43558

Citing AlgaeBase
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 24 February 2020.

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