Holotype species: Placentophora colensoi (J.D.Hooker & 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: 399-410.
Precise date of publication9 Jan 1976
Taxonomic status: currently recognized as a distinct genus.
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.
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 3 Sep 2011 by M.D. Guiry.
Comments: Distribution: Endemic to the North Island of New Zealand, where it occurs on rocks in strong surge from intertidal to 10 m depths.
Numbers of names and species: There is only one species or infraspecific name in the database at present, which has been flagged as accepted taxonomically on the basis of the listed literature under the species name. In some instances, opinions on taxonomic validity differ from author to author and users are encouraged to form their own opinion. AlgaeBase is a work in progress and should not be regarded as a definitive source only as a guide to the literature..
Names: ('C' indicates a name that is accepted taxonomically; 'S' a homotypic or heterotypic synonym; 'U' indicates a name of uncertain taxonomic status, but which has been subjected to some verification nomenclaturally; 'P' indicates a preliminary AlgaeBase entry that has not been subjected to any kind of verification. For more information on a species click on it to activate a link to the Species database):
Click here to also show infraspecific names in the list below.
Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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.
Created: 28 December 2000 by M.D. Guiry
Verified by: 03 September 2011 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=42567
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 21 March 2019.