Holotype species: Phaeosaccion collinsii Farlow
Original publication and holotype designation: Farlow, W. G. (1882). Notes on New England algae. Bulletin of the Torrey Botanical Club 9: 65-68.
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Kristiansen, J. & Preisig, H.R. (2001). Encyclopedia of Chrysophyte genera. Bibliotheca Phycologica 110: 1-260.
The genus may be referable to the Chrysomerophyceae (Gabrielson & Lindstrom 2018: 28). - (23 Feb 2018) - M.D. Guiry
Description: Thallus tubular to saccate, monostromatic, up to 20 cm long and 2 cm wide, olive-brown in color, resembling young plants of Scytosiphon. Thallus somewhat constricted at the base and enlarged towards the distal end, occurring in loose tufts attached by a small, polystromatic disc-like holdfast. Cells (up to 10 &m in diam.) arranged in fairly regular packets of 2's or 4's and embedded in a gelatinous matrix. A single parietal chloroplast, with a membrane-limited, embedded pyrenoid, visible in thin-sections only (Chen and others, 1974). Chrysolaminaran vacuoles and lipid droplets present. Zoospores formed singly from vegetative cells of mature thalli, about 10 &m in diam. with two, lateral, heterokont flagella. The anterior flagellum at least twice the length of the cell directs the cell forwards and bears tripartite mastigonemes; the shorter, posterior flagellum is acronematic. Zoospores negatively phototactic, with one chloroplast and a conspicuous stigma. No stomatocysts nor sexual reproduction recorded in culture. P. collinsii is a sublittoral marine alga, and generally occurs epiphytic on the leaves of the seagrass Zostera marina. An exclusively cold-water plant, it is distributed in boreal-arctic waters (northeast North America and northern Europe). Phaeosaccion was considered a member of the Phaeophyceae for almost a century. Morphological (McLachlan and others, 1971 ; Chen and others, 1974) and biochemical (Craigie and others, 1971) investigations definitely assigned this alga to the Chrysophyceae, where, with respect to size and morphology, P. collinsii is considered the largest and most advanced member. More data are needed to assess its true phylogenetic affinities.
Information contributed by: C. Billard. The most recent alteration to this page was made on 23 Feb 2018 by M.D. Guiry.
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):
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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.
Created: 22 May 2002 by Elizabeth Moran
Verified by: 23 February 2018 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=44795
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 16 November 2018.