Mesothamnion Børgesen, 1917

Holotype species: Mesothamnion caribaeum Børgesen

Currently accepted name for the type species: Pleonosporium caribaeum (Børgesen) R.E.Norris

Original publication and holotype designation: Børgesen, F. (1917). The marine algae of the Danish West Indies. Part 3. Rhodophyceae (3). Dansk Botanisk Arkiv 3: 145-240, figs 149-230.

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Description: Thallus erect, axes alternately branched spirally or distichously arranged, ecorticate, cells multinucleate. Procarp subterminal with sterile cell and 4-celled carpogonial branch on one (supporting cell) of 2 pericentrals. Apical cell displaced laterally allowing sterile cell on supporting cell to appear terminal. Auxiliary cell, cut off from supporting cell, leading to development of carposporophyte with rounded groups of carposporangia. Involucral filaments present. Spermatangial heads on upper cells of thallus. Tetrahedrally-divided tetrasporangia and polysporangia recorded. Combined with Pleonosporium by some authors on basis of similar procarp development and presence of tetrasporangia and polysporangia. Taxonomic clarification at tribal level required for these and other related genera.

Information kindly contributed by E.M. Wollaston but may now be outdated.

Taxonomic status: This name is currently regarded as a synonym of Pleonosporium.

Most recent taxonomic treatment adopted: Kylin, H. (1956). Die Gattungen der Rhodophyceen. pp. i-xv, 1-673, 458 figs. Lund: C.W.K. Gleerups.

Comments: Widespread in warm to temperate seas, usually epiphytic.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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.

Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=38036

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 22 October 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 18 April 2024