Nemastoma J., 1842, nom. cons.
Lectotype species: Nemastoma dichotomum J.Agardh
Original publication:Agardh, J.G. (1842). Algae maris Mediterranei et Adriatici, observationes in diagnosin specierum et dispositionem generum. pp. [i]-x, 1-164. Parisiis [Paris]: Apud Fortin, Masson et Cie.
Type designated in Schmitz, F. (1889). Systematische Übersicht der bisher bekannten Gattungen der Florideen. Flora oder Allgemeine botanische Zeitung 72: 435-456, pl. XXI.
Taxonomic status: currently recognized as a distinct genus.
Gender: This genus name is currently treated as neuter.
Most recent taxonomic treatment adopted: Schneider, C.W. & Wynne, M.J. (2007). A synoptic review of the classification of red algal genera a half a century after Kylin's "Die Gattungen der Rhodophyceen". Botanica Marina 50: 197-249.
The orthography "Nemastoma" has been conserved over "Nemostoma"; J. Agardh (1842: 89) also introduced the "Subtribus II. Nemostomeae" suggesting that the original spelling was not a lapsus. Three species were originally included: N. minor J.Agardh, N. marginata (Montagne) J.Agardh and N. dichotoma J.Agardh. Nemastoma dichotomum J.Agardh was chose by Schmitz (1889: 454). - (19 Oct 2015) - M.D. Guiry
Description: Thallus erect and uncalcified, mucilaginous, compressed to subterete with subdichotomous to irregular branching. Structure multiaxial, with a medulla of entwined filaments and a cortex of discrete subdichotomous branches; refractive gland cells usually present, terminal on cortical filaments. Carpogonial branches 3-4 celled, lacking a sterile-cell branchlet and borne on adventitious filaments. Auxiliary cell borne on adventitious filament, and lacking subsidiary cells. Gonimoblast outwardly developing, issued from connecting filament; nutritive cells absent. Carposporophyte lacking an ostiole. Spermatangia cut off from cortical cells; tetrasporophytes unknown (Ardré 1980; Masuda & Guiry 1994).
Information contributed by: G.T. Kraft; Robert Wilkes; A.D.R. N'Yeurt. The most recent alteration to this page was made on 24 Jan 2017 by M.D. Guiry.
Comments: The present widely held concept of Nemastoma defines it as containing linear to foliose plants in which gland cells are present and connecting filaments issue directly from carpogonia to fuse with generative auxiliary cells (Kraft and John 1976). Recent detailed study of the type species by Athanasiadis (1988) and Robins (pers. comm.), however, confirms the generally overlooked observations of Berthold (1884) that the carpogonial branches are restricted to adventitious rhizoids. In rare cases, gonimoblasts arise presumably auxiliary cells, that subtend the carpogonial branches and are not in contact with connecting filaments. Where connecting filaments are present, gonimoblasts arise from auxiliary carpogonial branches. Robins (pers. comm.) is of the opinion that only 2 or 3 species, possibly including Adelophycus, belong to Nemastoma as defined by the type species. Distribution: The type species occurs subtidally in the Mediterranean Sea, with a rarely collected second species, N. canariensis J. Agardh, from an unknown habitat in the Canary Islands.
Numbers of names and species: There are 49 species names in the database at present, as well as 8 infraspecific names. Of the species names, 10 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: 01 January 2001 by M.D. Guiry
Verified by: 24 January 2017 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=33003
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 12 December 2019.