Leptosomia J.Agardh, 1892
Lectotype species: Leptosomia cliftonii (J.Agardh) J.Agardh
Currently accepted name for the type species: Leptosomia rosea (Harvey) Womersley
Original publication: Agardh, J.G. (1892). Analecta algologica. Lunds Universitets ÅrsSkrift, Andra Afdelningen, Kongl. Fysiografiska Sällskapets i Lund Handlingar 28(6): 1-182, 3 pls.
Request PDFType designated in: Kylin, H. (1931). Die Florideenordung Rhodymeniales. Acta Universitatis Lundensis 27(11): 1-48, 8 figs, 20 pls.
Description: Thallus with erect irregularly laciniate, undulate blades, delicate, soft, gelatinous, usually with marginal lobes. Holdfast discoid. Structure multiaxial, cortex of 1-2 layers of small cells, medulla of 2-3 layers of large ovoid cells on either side of a central space in which coarse rhizoids develop, completely filling the space in older parts. Gametophytes and tetrasporophytes isomorphic. Gametophytes dioecious. Spermatangia formed from surface cells. Procarpic, carpogonial branch 3-celled, auxiliary cell branch 2-celled, gonimoblast developing outwards. Cystocarps ostiolate, scattered, never coronate, protruding outwards and inwards, tela arachnoidea absent. Tetrasporangia formed from intercalary inner cortical cells, scattered. Spores regularly cruciately arranged.
Information contributed by: M.D. Guiry. The most recent alteration to this page was made on 2010-10-08 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: This genus has been a source of much confusion. Womersley (1996) established that Leptosomia is characterized by its vegetative structure in which the central space between large, ovoid medullary cells becomes filled with coarse rhizoid as the fronds ages. It is surprising, however, that secretory cells known for other such Rhodymeniacean algae have not been reported. Only one rather large (to 50 cm) variable species is known from Western Australia and Victoria where it occurs at depths of up to 50 m; care may be necessary in separating this genus from Cenacrum, which, however, occurs mainly in subantarctic waters (Ricker, 1987). Plants are sometimes found growing epiphytically on seagrasses. Kylin (1956) referred four species of Leptosarca to Leptosomia, but these are now considered to be species of Palmaria (Ricker, 1987).
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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=40177
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 08 October 2010. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 19 April 2024
