153,615 species and infraspecific names are in the database, 20,981 images, 59,407 bibliographic items, 412,628 distributional records.

Lessonia Bory, 1825

Classification:
Empire Eukaryota
Kingdom Chromista
Phylum Ochrophyta
Class Phaeophyceae
Subclass Fucophycidae
Order Laminariales
Family Lessoniaceae

Holotype species: Lessonia flavicans Bory

Original publication and holotype designation: [Dumont] d'Urville, J.[B.G.M.] (1825). Flore des îles Malouines; par J. D'Urville. pp. [i], [1]-56. Paris: De l'imprimiere De Lebel, imprimeur du Roi.
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Taxonomic status: currently recognized as a distinct genus.

Most recent taxonomic treatment adopted: Silberfeld, T., Rousseau, F. & Reviers, B. de (2014). An updated classification of brown algae (Ochrophyta, Phaeophyceae). Cryptogamie Algologie 35(2): 117-156.

Description: Thallus 1-4 m high, perennial. Holdfast discoid, divided and becoming conical, or ligulate, attached by branched haptera, with the stipe branched from the base or higher, often twisted, with each branch bearing a blade. Blades simple, 0.5-2 m long and 1-5 cm wide, ligulate to irregularly elongate, flat, margins denticulate, surface smooth to rugose or corrugate. Growth by longitudinal splitting of the blades, resulting in dichotomous branching of stipe. Blade and stipe with a central, filamentous medulla, extensive cortex of relatively small cells with or without mucilage cavities, and outer layer of meristoderm. Spores produced in unilocular sporangia with paraphyses in extensive sori, produced on both surfaces of blades. Gametophytes dimorphic, dioecious, oogamous, branched uniseriate filaments.

Information contributed by: R.J. Lewis and M.D. Guiry. The most recent alteration to this page was made on 21 Jun 2014 by M.D. Guiry.

Comments: Lessonia is the only genus in the family Lessoniaceae to occur solely in the Southern Hemisphere, with 4 species recognized from South America and 5 from the south-west Pacific region. These species are morphologically variable, leading to description of many taxa in earlier taxonomic treatments. Several of these species are recently described, and further taxonomic revisions may be necessary. L. vadosa Searles, described from South America, may be conspecific with L. brevifolia J. Agardh, which occurs on the New Zealand subantarctic islands. The species are separated based on holdfast and stipe morphology, blade morphology (e.g. smooth or corrugate), and structural characteristics of the medulla and cortex in blades and stipes. L. nigrescens Bory and L. trabeculata Villouta & Santelices are harvested and exported from Chile for alginate extraction. L. nigrescens is the dominant organism in the low intertidal zone in central Chile while L. trabeculata forms extensive subtidal beds on rocky bottoms at depths of 0.5 to 20 m. Harvesting the upper portions of L. nigrescens greatly reduces its ability to survive, while harvesting entire plants increases grazing on remaining plants and makes neighboring plants susceptible to removal by water movement. Lessonia laminarioides Postels & Ruprecht from the Sea of Ochotsk has been removed from Lessonia and forms the basis for Pseudolessonia (Cho et al 2006).

Numbers of names and species: There are 29 species names in the database at present, as well as 5 infraspecific names. Of the species names, 11 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):

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

References
Searles, R.B. (1978). The genus Lessonia Bory (Phaeophyta, Laminariales) in southern Chile and Argentina. British Phycological Journal 13(4): 361-381.

Asensi, A. & de Reviers, B. (2009). Illustrated catalogue of types of species historically assigned to Lessonia (Laminariales, Phaeophyceae) preserved at PC, including a taxonomic study of three South-American species with a description of L. searlesiana sp. nov. and a new lectotypification of L. flavicans. Cryptogamie, Algologie 30(3): 209-249.

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.

Created: 28 December 2000 by M.D. Guiry

Verified by: 21 June 2014 by M.D. Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=42591

Citing AlgaeBase
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2018. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 19 November 2018.

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