Holotype species: Irvinea ardreana (J.Brodie & Guiry) Guiry
Original publication and holotype designation: Saunders, G.W., Strachan, I.M. & Kraft, G.T. (1999). The families of the order Rhodymeniales (Rhodophyta): a molecular-systematic investigation with a description of Faucheaceae fam. nov. Phycologia 38: 23-40.
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: Thallus consisting of erect branched stipes bearing inflated, ovoid, branched or unbranched vesicles formed sympodially and irregularly arranged, arising from a branched stoloniferous holdfast coalescing to form a discoid structure emitting further axes. Structure multiaxial, cortex of 2-3 layers of small cells, forming initially a discontinuous layer over the medullary cells, medulla of 1-2 layers of axially-elongated , rounded cells forming a compact tissue. Vesicles filled with a weak mucilage apparently from secretory cells borne in groups of 1-6 exclusively on morphologically differentiated cells formed on the inner faces of the medullary cells. Filamentous medulla absent. Life history a sequence of tetrasporangial gametangial and carposporangial phases, the gametophytes and tetraporophytes isomorphic. Gametangial plants dioecious; spermatangia in sori covering most of the mature vesicles, cut off from elongate initials formed from cortical cells. Procarpic, carpogonial branches 4-celled, borne on inner cortical supporting cells also bearing a 2-celled auxiliary cell branch, carposporophyte directed outwardly from a basal fusion cell, forming 2-3 synchronously developing lobes of carposporangia in different stages of maturity; a few, slender, stretched cells, perhaps with a nutritive function, persisting in the mature cystocarp. Cystocarps protruding strongly outwards, ostiolate with a thick pericarp. Tetrasporangia in ill-defined sori borne on the mature vesicles, formed in an intercalary position from cortical filaments. Spores regularly or irregularly cruciately arranged.
Information contributed by: M.D. Guiry. The most recent alteration to this page was made on 8 Oct 2010 by M.D. Guiry.
Comments: Irvinea ardreana was initially included in the genus Botryocladia by Brodie and Guiry (1988) with some reservations. A subsequent molecular-systematic investigation of this species and others referred to Botryocladia resulted in this entity being referred to a segregate genus, Irvinea. Strongly protruding cystocarps, the formation of cortical cells in rosettes, and, possibly, the formation of secretory cells on special initials circumscribe Irvinea and separate it from other Rhodymeniacean genera. Detailed investigations of other Botryocladia are required. Brodie and Guiry (1988) found that cultured plants of Irvinea ardreana from Portugal would not grow at 5°C, did not reproduce at 10°C, formed tetrasporangia and gametangial at 15°C, long days and short days, but grew and reproduced most rapidly at 20°C, long days, completing a life history cycle in about one year.
Numbers of names and species: There are 3 species names in the database at present, of which 3 have 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: 28 December 2000 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=42617
Please cite this record as:
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.