Polyostea Ruprecht, 1850
Lectotype species: Polysiphonia urceolata (Lightfoot ex Dillwyn) Greville
Currently accepted name for the type species: Polysiphonia stricta (Mertens ex Dillwyn) Greville
Original publication: Ruprecht, F.J. (1850). Algae ochotenses. Die ersten sicheren Nachrichten über die Tange des Ochotskischen Meeres. pp. 1-243, 10 pls. St. Petersburg: Buchdruckerei der Kaiserlichen Akademie der Wissenschaften.
Type designated in: Savoie, A.M. & Saunders, G.W. (2016). A molecular phylogenetic and DNA barcode assessment of the tribe Pterosiphonieae (Ceramiales, Rhodophyta) emphasizing the Northeast Pacific. Botany 94: 917-939, 8 figs.
Description: Thalli polysiphonous with 4–14 pericentral cells, ecorticate, lacking trichoblasts; both prostrate and erect axes cylindrical, erect axes arising from a prostrate basal system; prostrate axes attached to the substrate by unicellular rhizoids, rhizoids cut off from pericentral cells; erect axes 150–350 m in diameter, with generally alternate-distichous branching (especially in upper parts), despite radial development of laterals at the apices; branching to several orders, with laterals arising at regular intervals of two or three successive segments, proximal segments of laterals fused with the bearing axis over 0.5–1.5 segments, terminal ramuli often incurved and overtopping the apices (giving the appearance of sympodial growth). Tetrasporangia tetrahedral, with two cover cells, occurring one per segment in straight series in ultimate and subultimate branches. Cystocarps are globular to ovoid, on short pedicels. Spermatangia known only from P. robusta, spermatangial branches cylindrical, on short branchlets on ultimate laterals, with 3–4 celled sterile apices.
Information kindly contributed by A.M.Savoie & G.W.Saunders but may now be outdated.
Taxonomic status: This name is currently regarded as a synonym of Polysiphonia.
Gender: This genus name is currently treated as feminine.
Most recent taxonomic treatment adopted: Wynne, M.J. (2018). The status of Polyostea Ruprecht (1850) and the proposal of Savoiea gen. nov. (Rhodomelaceae, Rhodophyta). Notulae Algarum 69: 1-4.
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Some of the descriptions included in AlgaeBase were originally from the unpublished Encyclopedia of Algal Genera, organised in the 1990s by Dr Bruce Parker on behalf of the Phycological Society of America (PSA) and intended to be published in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=42654
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 17 May 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 01 October 2022