Sphaerotrichia Kylin, 1940
Holotype species: Sphaerotrichia divaricata (C.Agardh) Kylin
Original publication and holotype designation: Kylin, H. (1940). Die Phaeophyceenordnung Chordariales. Acta Universitatis Lundensis 36(9): 1-67, 30 figs.
Request PDFDescription: Plants epilithic or epiphytic, attached by small disc, solitary or caespitose, terete, solid later becoming hollow, slightly gelatinous, irregularly dichotomously or alternately branched several times, gradually attenuated towards apex, yellowish to dark brown in color, haplostichous, composed of several layers of colorless, large, elongated medullary filaments, pigmented roundish cortical cells and 3-5 celled assimilatory filaments. Each cell contains several chloroplasts with pyrenoids. Rhizoidal filaments often present in the central hollow area. Terminal cells of assimilatory filaments obviously swollen and larger than the cells below them. Unilocular sporangia formed on entire thallus, on basal cells of assimilatory filaments, ovate, pyriform, up to 140 µm in length and 25 µm in diameter. Phaeophycean hairs scattered and abundant. Plurilocular sporangia not detected on erect thalli.
Information contributed by: H. Kawai. The most recent alteration to this page was made on 2014-06-20 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Silberfeld, T., Rousseau, F. & Reviers, B. de (2014). An updated classification of brown algae (Ochrophyta, Phaeophyceae). Cryptogamie Algologie 35(2): 117-156, 1 fig., 1 table.
Comments: Mainly distributed in temperate area of Pacific and Atlantic Ocean. Recently introduced to Mediterranean coast. In recent culture studies, Ajisaka and Umezaki (1978) cultured Japanese S. divaricata and reported typical heteromorphic life history with sexual reproduction. Unispores developed into bushy filamentous gametophytes forming uniseriate plurilocular sporangia. Those plurispores copulated and the zygote developed into erect thalli forming unilocular sporangia. Unfused gametes reproduced gametophytes. Chromosome counts in diploid sporophyte 2n = 18-24. Peters and others (1987) cultured several strains of S. divaricata from North Pacific and North Atlantic and showed sexual heteromorphic life history between dioecious filamentous gametophytes and erect thalli, or asexual direct type of reproduction according to the strains. They reported the chromosome number of S. divaricata as n = 14-18.
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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=32918
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 20 June 2014. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 03 December 2024
