Laurencia J.V.Lamouroux, 1813, nom. cons.

Lectotype species: Laurencia obtusa (Hudson) J.V.Lamouroux

Original publication: Lamouroux, J.V.F. (1813). Essai sur les genres de la famille des Thalassiophytes non articulées. Annales du Muséum d'Histoire Naturelle 20: 21-47, 115-139, 267-293, 7 plates [7-13].

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Type designated in: Schmitz, F. (1889). Systematische Übersicht der bisher bekannten Gattungen der Florideen. Flora oder Allgemeine botanische Zeitung 72: 435-456, pl. XXI.

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Description: Thallus erect or decumbent, cartilaginous or not; branches arranged distichously, radially or whorled. Axes terete or flattened, with an apical pit from which an inconspicuous tuft of trichoblasts emerges. Structure polysiphonous, the central axial cells cutting off 4 pericentral cells, but these normally indistinct within a few segments of the apices. In transverse section view, the first pericentral cell is positioned underneath the trichoblast basal cell. Medulla of large hyaline cells, grading to a cortex of smaller pigmented cells. Outer cortical cells never forming a palisade, in section nearly isodiametric or radially elongate, rounded to angular; in some species with projecting outer walls. Outer cortical cells developing lateral secondary pit connections (best seen in longitudinal section), and in many species containing bright cell inclusions (corps en cerise). Medullary cells in some species with thickened opaque walls or lenticular thickenings (lens-like inclusions within medullary cells). Spermatangia forming on fertile trichoblasts. Procarp bearing a segment of 5 pericentral cells. Auxiliary cell formation after fertilisation is normal (as opposed to the delayed formation seen in Chondrophycus). Cystocarps usually lateral on fertile branchlets, conspicuous. Tetrasporangia developing from pericentral cells, tetrahedrally divided, arranged in vague lines along sides of fertile branches, parallel to the axis (parallel arrangement). Two or three pericentral cells developing from a tetrasporangial axial cell.

Information contributed by: Metti, Huisman & Millar (2018).. The most recent alteration to this page was made on 2018-10-09 by M.D. Guiry.

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

Gender: This genus name is currently treated as feminine.

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.

Comments: Occurring on temperate to tropical shores of the world, littoral to sublittoral up to 65 m deep

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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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M.D. Guiry in Guiry, M.D. & Guiry, G.M. 09 October 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway.; searched on 21 May 2024

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