Cladostephus C., 1817
Lectotype species: Cladostephus spongiosus (Hudson) C.Agardh
Original publication:Agardh, C.A. (1817). Synopsis algarum Scandinaviae, adjecta dispositione universali algarum. pp. [i]-xl, -135. Lundae [Lund]: Ex officina Berlingiana.
Type designated in Bonnemaison, T. (1822). Essai d'une classification des hydrophites loculées, ou plantes marines articulées qui croissent en France. Journal de Physique, de Chimie, d'Histoire Naturelle et des Arts 94: 138-148; 174-203.
Taxonomic status: currently recognized as a distinct genus.
Gender: This genus name is currently treated as masculine.
Most recent taxonomic treatment adopted: Heesch, S., Rindi, F., Guiry, M.D. & Nelson, W.A. (2020). Molecular phylogeny and taxonomic reassessment of the genus Cladostephus (Sphacelariales, Phaeophyceae). European Journal of Phycology 55(4): [1-18] 426-443.
The genus Cladostephus was apparently formed from clados, a branch and stephos, a wreath or crown (Newton 1931); as stephos is neuter (Stearn 1973), Atthansiadis (1996) treated as neuter. However, nomenclatural tradition treats genera with the suffix -stephus as maculine, and the genus is treated as such in ING. - (2 May 2015) - M.D. Guiry
Description: Plants forming 5-25 (-40) cm tall, yellowish brown to dark brown or olivaceous, epilithic, erect, spreading bushes or isolated groups of (1-) 2-5 heterotrichous axes. Basal parts consisting of small or extensive, polystromatic, crustose discs. Axes and indeterminate laterals long and prominent, erect, terete, auxocaulous, brown or blackish, with smooth surface, more or less wiry. Branching of several orders, in indeterminate axes hemiblastic and pseudodichotomous; determinate laterals in whorls, densely crowded or distinctly verticillate, stiff, divaricate, straight or upwardly curved, unbranched or scarcely acroheteroblastically branched. Occasionally a lenticular branch initial is formed from the conspicuous cylindrical apical cell of the determinate laterals before a segment is cut off. Segments each divide transversely once before frequent longitudinal and transverse segmentation and secondary growth. Internal structure of axes consisting of cubical medullary cells, a pseudoparenchymatous inner cortex of enlarging cells and in older parts a small-celled outer cortex, formed by appressed rhizoids. Loose descending rhizoids absent. Hairs in clusters in axils of small laterals of branched determinate laterals. Pericysts occasional, in young segments of indeterminate axes. Reproductive structures: pedicellate plurilocular isogametangia and pedicellate unilocular zoidangia borne laterally on crowded, meriblastic, fertile, determinate laterals, which arise from the axes. Cosmopolitan marine in the tidal zone and in sublittoral, restricted to temperate regions. Unattached forms occur occasionally in seagrass meadows. These sterile forms with only few laterals in each worl propagate only by fragmentation. The diplohaplontic life history is isomorphic, isogamic and probably monoecious. Parthenogenesis as well as ephobogenesis has been observed. Basal chromosome number not known.
Information contributed by: Prud'homme van Reine. The most recent alteration to this page was made on 24 Jun 2020 by M.D. Guiry.
German: Echter Seequirl (Braune 2008).
Numbers of names and species: There are 21 species names in the database at present, as well as 9 infraspecific names. Of the species names, 5 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: 29 December 2000 by M.D. Guiry
Verified by: 24 June 2020 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=49
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 27 September 2021.