Maripelta E.Y.Dawson, 1963

Holotype species: Maripelta rotata (E.Y.Dawson) E.Y.Dawson

Original publication and holotype designation: Dawson, E.Y. (1963). Marine red algae of Pacific Mexico. Part 6. Rhodymeniales. Nova Hedwigia 5: 437-476, pls 77-95.

Precise date of publication: 31 Jan 1963

Description: Thallus erect, peltate with simple, membranous, rotate, deciduous, sometimes iridescent blades expanding from the apices of cylindrical, branched or unbranched stipes. Construction multiaxial, cortex of 2-3 layers of small cells sometimes with hair cells. Medulla of a single layer of very large, thick-walled, colourless cells visible through the cortex. Gametangial plants dioecious. Spermatangial sori superficial, spermatangia borne singly in a terminal position on cortical cells. Procarpic, carpogonial branches in cortex, 3- or 4-celled, formed on a large supporting cell with a single 2-celled auxiliary cell branch, gonimoblast developing outwards from a large fusion cell. Cystocarps ostiolate, sometimes with a raised collar around the ostiole, scattered, never coronate, strongly protruding outwards, most cells forming carposporangia in 2-3 lobes of different ages, tela arachnoidea absent. Tetrasporangia formed in an intercalary position from cortical cells. Sori nemathecioid, scattered on the upper surface of the blade or in a continuous ring on the lower surface. Spores regularly cruciately arranged. Carpospores from plants collected in the subtidal of the Monterey Peninsula, California, gave rise to peltate plants that have grown well in enriched seawater at low photon irradiances (2-3 µmol m-2 s-1) at 15%C for over 15 years, periodically shedding the rotate blades and giving rise to new crops of blades from the stipes, but which have never reproduced (West, Moe and Guiry, unpubl.). The life history is thus probably of the 'Polysiphonia-type.'

Information contributed by: M.D. Guiry. The most recent alteration to this page was made on 2011-08-30 by M.D. Guiry.

Taxonomic status: This name is of an entity that is currently accepted taxonomically.

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: Two other genera of Rhodymeniales form peltate blades: Halichrysis and Sciadophycus. Halichrysis (q.v.) has a polystromatic medulla and the peltate blades are imbricate in mature plants. In Sciadophycus (q.v.), branching of the peltate blades takes place by means of proliferation from the margins, cystocarps possess a tela arachnoidea and the tetrasporangia are terminal. Maripelta rotata is known from the coast of California and Baja California, where it grows in the subtidal up to depths of 79 m and has been found in the shade of Macrocystis beds at a depth of 13 m. M. atlantica Eiseman et Moe (1981) has been collected from the Atlantic and Caribbean coasts of Florida where it grows at depths of 20-100 m, in certain places becoming a dominant member of the flora. The thallus form of these two deep-water peltate algae suggests adaptation to low-light conditions; surface area to volume ratios are maximized and the horizontally-orientated blades act as light-collecting dishes. M. rotata has spermatangia and tetrasporangia in scattered sori on the upper surface of the blade, whereas M. atlantica has tetrasporangia in a continuous, submarginal ring on the lower surface of the blade and spermatangia in a ring on the upper surface. In both species the cystocarps develop submarginally, but those of M. atlantica appear to be produced closer to the margins than those of M. rotata.

Verification of Data
Users are responsible for verifying the accuracy of information before use, as noted on the website Content page.

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=42466

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 30 August 2011. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 26 April 2024