152,885 species and infraspecific names are in the database, 20,939 images, 59,127 bibliographic items, 408,269 distributional records.

Leptosomia J.Agardh, 1892

Classification:
Empire Eukaryota
Kingdom Plantae
Subkingdom Biliphyta
Phylum Rhodophyta
Subphylum Eurhodophytina
Class Florideophyceae
Subclass Rhodymeniophycidae
Order Rhodymeniales
Family Rhodymeniaceae

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. Acta Universitatis Lundensis 28(6): 1-182, 3 pls.
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Type designated in Kylin, H. (1931). Die Florideenordung Rhodymeniales. Acta Universitatis Lundensis 27(11): 1-48, 8 figs, 20 plates.

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.

Taxonomic notes
Schneider & Wynne (2007: 206) note that Leptosarca, which Kylin (1956) had treated as congeneric with Leptosomia, was subsumed by Ricker (1987) within Palmaria. - (15 Oct 2010) - Wendy Guiry

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 8 Oct 2010 by M.D. Guiry.

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).

Numbers of names and species: There are 7 species names in the database at present, of which 1 has 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):

Click here to also show infraspecific names in the list below.

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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.

Created: 28 December 2000 by M.D. Guiry

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Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=40177

Citing AlgaeBase
Please cite this record as:
Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 September 2018.

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