Siphonocladus F.Schmitz, 1879

Lectotype species: Siphonocladus wilbergii F.Schmitz

Currently accepted name for the type species: Siphonocladus pusillus (C.Agardh ex Kützing) Hauck

Original publication: Schmitz, F. (1879). Über grüne Algen im Golf von Athen. Berichte der Sitzungen der Naturforschenden Gesellschaft zu Halle 1878: 17-23.

Type designated in: Børgesen, F. (1905). Contributions à la connaissance du genre Siphonocladus Schmitz. Oversight Over Det Kgl Danske Videnskabernes Selskabs Forhandlingar 3: 259-291, 13 figs.

Description: Thallus composed of many free, unbranched and branched elongate axes, 1-3 mm diameter, to 4 cm tall. Each axis consisting of a pseudoparenchymatous filament of appressed, polygonal cells. Cells 200-500 µm diameter. Plants with prominent basal annular constrictions. Apical, uniaxial orientation maintained throughout development in most species. Branching pattern irregular. Lateral papillate branchlets, to 1 cm long, in whorls found in some species. Well developed rhizoids present. Structural reinforcement of thallus achieved by specialized tenacular cells. Cell division by segregative division - sensu stricto in main axes, by centripetal invagination in rhizoids. Cells multinucleate; chloroplasts numerous per cell. The life history of Siphonocladus pusillus was studied by Jónsson and Puiseaux-Dao in which they suggested a diplontic life history. In most cladophoralean genera a diplobiontic, isomorphic alternation of generations has been demonstrated. Vegetative propagation is common. S. pusillus and S. tropicus with diploid chromosome number of 16. Nuclear DNA estimated at 1.1, 2.0 and 4.4 pg (1C, 2C, 4C) for S. tropicus. Siphonocladus commonly found in shallow intertidal habitats exhibiting strong water motion and turbidity. Plants attached on rubble though they can also be found in more protected crevices. S. rigidus also abundant in metahaline near-shore pool in the Red Sea. Ultrastructural studies on the flagellar apparatus and cytokinesis and cell walls carried out. Siphonocladus used in studies of role of microtubules in biogenesis of cellulose microfibrils. Siphonocladus has been variously allied with Valonia and Cladophoropsis based on segregative division and habit, respectively. Siphonocladus is most closely related to Dictyosphaeria and most distantly to Ventricaria based on immunologic and character compatibility analyses. Siphonocladus is not related to Boergesenia or Cladophoropsis as suggested in most circumscriptions emphasizing annular constrictions.

Information contributed by: J.L. Olsen. The most recent alteration to this page was made on 2011-08-29 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

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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.

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Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 29 August 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024