Placentophora Kraft, 1976

Holotype species: Placentophora colensoi (Hooker f. & Harvey) Kraft

Original publication and holotype designation: Kraft, G.T. (1976 '1975'). Morphology of Placentophora (Solieriaceae, Gigartinales: Rhodophyta), a new genus based on Sarcodiotheca colensoi from New Zealand. Journal of Phycology 11(4): 399-410.

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Precise date of publication: 9 Jan 1976

Description: Plants reach 30 cm in length and are erect from a fleshy discoid holdfast. Thallli are flattened, linear, distichously and pinnately branched, and generally lined by short marginal teeth toward the extremities. Apices are multiaxial, the medulla being broad and filamentous, the cortex composed of progressively smaller subisodiametric cells. Carpogonial branches are 3-celled, the carpogonia apparently giving rise to a single connecting filament on fertilization. Auxiliary cells come to be surrounded by clusters and branched chains of nutritive cells. Inwardly growing gonimoblast filaments incoporate the nutritive-cell region into a broad placenta where many partial fusions between gametophytic and carposporophytic cells take place. Short, branched gonimoblasts arise around the periphery of the placenta and bear chains of carposporangia. Cystocarps form in clusters deeply buried in the axes, are ostiolate, and lack a strongly defined pericarp with an inner filamentous hull. Spermatangial clusters are sunken in the cortex between paraphysis-like sterile cells. Tetrasporangia are basally anchored to bearing cells.

Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 2020-02-03 by M.D. Guiry.

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

Most recent taxonomic treatment adopted: Dumilag, R.V., Nelson, W.A. & Kraft, G.T. (2019). Validation and phylogenetic placement of the Placentophoraceae fam. nov. (Gigartinales, Rhodophyta). Phycologia 58(3): 269-275, 13 figs.

Comments: Distribution: Endemic to the North Island of New Zealand, where it occurs on rocks in strong surge from intertidal to 10 m depths.

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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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=42567

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 03 February 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 28 March 2024

 
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