Ahnfeltia E.M.Fries, 1836, nom. cons.

Lectotype species: Ahnfeltia plicata (Hudson) E.M.Fries

Original publication: Fries, E.M. (1836). Corpus florarum provincialium Sueciae. I. Floram scanicam. pp. 193-346. Upsaliae [Uppsala]: excudebant Regiae Acad. Typographi.

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Type designated in: Ruprecht, F.J. (1850). Algae ochotenses. Die ersten sicheren Nachrichten ├╝ber die Tange des Ochotskischen Meeres. pp. 1-243, 10 pls. St. Petersburg: Buchdruckerei der Kaiserlichen Akademie der Wissenschaften.

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Description: As the only genus in the Ahnfeltiales, its ordinal features include carpogonia that terminate filaments of normal cortical anatomy within swollen nemathecia and which fuse facultatively with morphologically unmodified contiguous cortical cells following fertilization. No differentiated auxiliary cells. Gonimoblast filaments spread directly from the carpogonium over the surface of the sorus, fusing with vegetative and other gonimoblast cells, and radiating outward to terminate in carposporangia. Pit plugs lack cap layers and cap membranes, and walls contain agarocolloids. Family features include gametophytes growing erect from a discoid base, multiaxial fronds with vegetative cells forming conjunctor cells resulting in secondary pit connections, and also fusing directly. Spermatangia cut off singly and transversely from surface mother cells. Sexual reproduction is as above, several embryos developing from adjacent zygotes for form compound external carposporophytes not surrounded by a gametophytic pericarp. Modified cortical cells of male gametophytes also form monosporangia, the monospores recycling the male gametophytic generation. Tetrasporophytes crustose, the crusts exhibiting direct cell fusions but lacking secondary pit connections. Tetrasporangia irregularly zonate occurring apically in sori.

Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 2017-01-20 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: Ahnfeltia thalli reach 21 cm in length. The type species is widespread, circumpolar and in both hemispheres. Other species are less widely distributed.

The type species is circumpolar in both hemispheres, ranging from Greenland, Spitzbergen, Iceland and northern Norway in the east to the Bering Straits, Alaska, Siberia, Manchuria and China in the west. In the Southern Hemisphere it is recorded from the Antarct subantarctic islands, and southern South America (Ricker 1987). Ahnfeltia fastigiata (Postels and Ruprecht) Makienko occurs from the Aleutian Islands to northern Baja California in the east to as far south as North Korea in the west. Ahnfeltia elongata is endemic to south-central Chile.

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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=21

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 20 January 2017. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 16 July 2024

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