Holotype species: Haemescharia polygyna Kjellman
Original publication and holotype designation: Kjellman, F.R. (1885 '1883'). The algae of the Arctic Sea. A survey of the species, together with an exposition of the general characters and the development of the flora. Kongliga Svenska Vetenskaps-Akademiens Handlingar 20(5): 1-351, 31 pls.
Precise date of publicationNone
Taxonomic status: currently recognized as a distinct genus.
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.
Monotypic when first introduced. - (23 Jan 2017) - M.D. Guiry
Description: Crusts reach 5 cm in diam. and have soft but firm textures. Erect filaments produce one to a few non-pigmented laterals of unknown function. Hypogynous cells sometimes bear a single sterile lateral cell, although some possibly non functional carpogonia are sessile on supporting cells. Tetrasporangia are cuboidal in shape.
Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 23 Jan 2017 by M.D. Guiry.
Comments: The identity of this long-debated genus (Denizot 1968) has finally been established by Wilce and Maggs (1989). The catenate, cruciate sporangia, division of the fertilized carpogonium, emission of numerous connecting filaments, and initiation of goniomoblasts from the fusion site of the connecting filament adjacent to the auxiliary cell distinguish the genus from superficially similar non-calcified crusts belonging to the Peyssonneliaceae, Cruoriaceae, Ganiaceae and Blinksiaceae, as well as from foliose genera with encrusting tetrasporophytes belonging to the Gigartinaceae, Petrocelidaceae and Phyllophoraceae. Distribution: The type species appears to be circumpolar, having been recorded in Greenland, adjacent Canadian islands and Siberia. Plants are generally collected from 3-10 m depths, with exceptional records coming from 46 m. The second species, H. hennedyi (Harvey) Wilce and Maggs, occurs from Norway to the British Isles and in northeastern Canada, and has long been known as Petrocelis hennedyi. In Ireland it occurs intertidally down to 10 m depths. Family of one genus and two species. Plants are uncalcified crusts on rocks, encrusting Corallinaceae, or frondose algae and consist of a basal horizontal layer of cells from each of which one or two erect filaments arise dorsally. Rhizoidal anchoring filaments may or may not be present. Cell fusions and secondary pit connections are lacking. Spermatangia are very elongate (to 24 um in length) and borne in clusters on intercalary mother cells in monoecious gametophytes. Supporting cells are intercalary and bear single or pairs of 2-celled carpogonial branches directed towards the frond surface. Auxiliary cells are intercalary in positions comparable to supporting cells. Following fertilization the carpogonium divides into two uninucleate derivative cells which, together with the hypogynous cell, initiate up to 8 branched, septate or non-septate, connecting filaments. Auxiliary cells fuse to connecting filaments at a protrusion on the auxiliary cell, the connecting filaments then growing on to effect further diploidizations. One or two goninmoblast initials arise thallus-outwardly from the fusion site adjacent to the auxiliary cell and develop into an ovoid to linear cluster of 32-64 carposporangia borne on few if any inner sterile gonimoblast cells. Gametangaia and tetrasporangia are both aggregated into indistinct soral areas. Tetrasporangia form as single or chains of up to 8 intercalary initials that divide irregularly cruciately.
Numbers of names and species: There are 2 species names in the database at present, of which 2 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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Verification of data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.
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
Verified by: 23 January 2017 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=37708
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 January 2019.