Porphyropsis Rosenvinge, 1909
Holotype species: Porphyropsis coccinea (Areschoug) Rosenvinge
Original publication and holotype designation: Rosenvinge, L.K. (1909). The marine algae of Denmark. Contributions to their natural history. Part I. Introduction. Rhodophyceae I. (Bangiales and Nemalionales). Kongelige Danske Videnskabernes Selskabs Skrifter, 7. Række, Naturvidenskabelig og Mathematisk Afdeling 7: 1-151, 73 figs, 2 pls, 2 folded charts.
Description: Foliose, monostromatic thalli typically 10-20 mm in length (up to 60 mm) arise from a basal cushion of cells. Foliose blades thin and diaphanous, composed of small vegetative cells (3-6 um in diameter) surrounded by abundant wall matrix. Each cell contains a single parietal chloroplast lacking a pyrenoid. Contains B-Type II phycoerythrin. Growth is diffuse, but may be apical in the early developmental stages. Pit plugs absent. Cells at the junction of the blade and basal cushion form short rhizoids. Asexual reproduction by monospores. Cells of the foliose thalli undergo unequal cytokinesis to produce two unequal sized cells, the smaller of which forms a monosporangium. Archeospores can also be produced when the entire content of a vegetative cell is transformed into an archeosporangium which will eventually release a single archeospore. At an ultrastructural level archeosporangia can be distinguished from vegetative cells by the numerous fibrillar vesicles of mucopolysaccharide that they contain. Released monospores and archeospores germinate to form a monostromatic, filamentous crust with filaments united centrally, but free at their margins. Crusts eventually become several cells thick and form a hollow cushion of cells in the central part of the disk. A splitting of this central bladder of cells gives rise to the monostromatic foliose blade. Sexual reproduction has not been documented, however putative spermatangia are formed by an unequal cytokinesis similar to that which gives rise to monosporangia. At an ultrastructural level these presumed spermatangia lack chloroplasts and contain numerous fibrillar vesicles as is the case in other red algal spermatangia. Growing in the subtidal (or occasionally in the low intertidal) on rock or other algae to depths of 25 m.
Information contributed by: M. Hawkes. The most recent alteration to this page was made on 2011-05-15 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: Little is known about the seasonality of this genus, but the bladed phase appears in the spring and summer. Cosmopolitan in distribution, being reported from the European Atlantic, the north Pacific, and Australia.
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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.
Linking to this page: https://www.algaebase.org/search/genus/detail/?genus_id=83
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 15 May 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 27 March 2023