Gainia R.L.Moe, 1985
Holotype species: Gainia mollis R.L.Moe
Original publication and holotype designation: Moe, R.L. (1985). Gainia and the Gainiaceae, a new genus and family of crustose marine Rhodophyceae from Antarctica. Phycologia 24: 419-428.
Request PDFDescription: Plants are soft, non-calcified crusts. The hypothallus consists of one to several loosely arranged layers of prostrate filaments, with cells of their upper layers giving rise to a perithallus of erect, parallel filaments. Cells are uninucleate throughout, and secondary pit connections are absent. Gametangia are formed in nemathecia, the carpogonial branches being 3-4-celled and terminating erect filaments surrounded by extended, paraphysis-like filaments. Auxiliary cells are intercalary in short nemathecial filaments similar in structure to carpogonial filaments. Fertilization is followed, in at least some cases, by fusion of the carpogonium with the basal cell of the carpogonial branch and, apparently, by initiation of connecting filaments. Connecting filaments terminate at auxiliary cells, and gonimoblasts arise in a thallus-outwardly direction from a site on the connecting filament adjacent to its point of fusion to the auxiliary cell. Cystocarps are embedded, globular, without ostioles, and composed almost completely of carposporangia. Tetrasporophytes are isomorphic with gametophytes, the tetrasporangia terminating otherwise normal perithallial filaments and dividing in an irregularly cruciate to zonate manner. Individual crusts can cover up to 100 m2 in area, reach 1.5 mm in thickness, and are attached directly to the substratum, without anchoring rhizoids. mucilaginous, the perithallial filaments separating fairly easily under pressure. Refractive cells, possibly of "glandular" nature, occur laterally on some perithallial cells. Spermatangial patches lack paraphyses, the mother cells forming in chains at the ends of perithallial filaments and cutting off either 1-2 spermatangia directly or additional 1-2 spermatangial mother cells. Auxiliary cells are differentiated prior to diploidization. Gonimoblast initials give rise to 1-4 gonimolobes. [Noncalcareous, soft, thick, saxicolous crust. Hypothallus without rhizoids, of one to several layers. Perithallus of sparingly branched, loosely coherent filaments. Cells uninucleate, without secondary pit connections or fusions. "Gland" cells present. Female reproductive structures in nemathecia. Supporting cell of 3-celled carpogonial branch terminal on perithallial filament. Carpogonium fusing with first cell of branch following fertilization. Auxiliary cell the basal cell of a 3-6-celled extension of a perithallial filament. A single gonimoblast initial arising from a distal process of the auxiliary cell or from the non-septate connecting filament near the auxiliary cell, producing 1-4 gonimolobes. All but basal cells of gonimolobe maturing into small carposporangia. Filaments of the nemathecium abscising after release of carpospores. Spermantangia produced by a terminal chain of short cells. Tetrasporophyte isomorphic. Tetrasporangia small, terminal on perithallial cells, irregularly cruciate or irregularly zonate, attached basally]
Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 2010-10-07 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Gender: This genus name is currently treated as feminine.
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.
Comments: Distribution: Endemic to the Antarctic continent, where it occurs on encrusting coralline red algae and rocks at 6-25 m depths along the Antarctic Peninsula in the west and at Davis in the east. [Known only from the subtidal of Antarctica.]
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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=42794
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 07 October 2010. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 16 April 2024
