157,571 species and infraspecific names are in the database, 22,210 images, 60,987 bibliographic items, 459,373 distributional records.

Eisenia Areschoug, 1876

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

Holotype species: Eisenia arborea Areschoug

Currently accepted name for the type species: Ecklonia arborea (Areschoug) M.D.Rothman, Mattio & J.J.Bolton

Original publication and holotype designation: Areschoug, J.E. (1876). De tribus Laminarieis (Egregia Aresch., Eisenia Aresch., Nereocystis) et de Stephanocystide osmundacea (Turn.). Trevis. observationes praecursorias offert. Botaniska Notiser 1876: 65-73.

Taxonomic status: currently regarded as a synonym of Ecklonia.

Most recent taxonomic treatment adopted: Rothman, M.D., Mattio, L., Wernberg, T., Anderson, R.J., Uwai, S., Mohring, M.B. & Bolton, J.J. (2015). A molecular investigation of the genus Ecklonia (Phaeophyceae, Laminariales) with special focus on the southern hemisphere. Journal of Phycology 51(2): 236-246.

Description: Life history diplohaplontic with alternation of large sporophyte bearing unilocular meiosporangia with paraphyses (sori) and microscopic dioecious and oogamous, heteromorphous gametophytes (for detail, see Laminaria). Haploid chromosome number is 15 in E. arborea (Hollenberg 1939) and 27-29 in E. bicyclis (Ohmori 1967). Sporophyte perennial. Six years is estimated life-span for E. bicyclis (Taniguchi & Kato 1984). Holdfast massive, with dichotomously branched haptera. Stiff, woody stipe up to ca. 1 m tall and bifurcate above, extending into 2 flattened lobes bearing many lateral blades, the sporophylls. The bifurcation is the thickened lower margin of the primary terminal, simple and undivided blade which erodes after some time leaving a small partial blade at outer extremity of each false stipe with 2 meristem regions. These give rise to the sporophylls along the lower outer margin. Sori develop on sporophylls as irregular patches. Structure of sporophyte as in Laminaria composed of photosynthetic meristoderm, parenchymatic cortex and central medulla. There is a strong seasonality of growth and reproduction in E. bicyclis. Each year up to ca. 40 sporophylls are formed and discarded lateron. Rapid growth takes place from January to August, slow growth from September to December. Although sori are present throughout the year, new sori on young blades appear from late summer onwards (Taniguchi et al. 1991).

Information kindly contributed by I. Bartsch but may now be outdated.

Comments: Photosynthetic rate of E. bicyclis plants from 2, 4 and 5 m depths is saturated at a photon fluence rate of ca. 185 µmol m-2 s-1. Depth limitation of this species is calculated to be at 1.2% of the light intensity at water surface (Maegawa et al. 1987). Population density of newly germinated plants is affected by density of adults (reduced light intensity) and temperature, with high recruitment at low temperatures (Taniguchi and Kito 1988) although gametophytes survive up to 30°C for 2 weeks (tom Dieck 1993). The genus is endemic to warm-temperate waters in the Pacific with two very similar species in Japan (E. bicyclis) and the west coast af USA from Vancouver islands to Baja California (E. arborea). Along the Peruvian coast grow E. gracilis and E. cokeri, the latter probably conspecific to E. arborea. Additionally there are deep-water species: E. desmarestioides and E. masonii at Isla Guadeloupe in Baja California and E. galapagensis in the Galapagos Archipelago. The deep-water species and young Eisenia plants are similar to the genus Ecklonia. In Japan, intergeneric and interspecific crosses were successful between the 4 species Ei. bicyclis, Ec. cava, Ec. stolonifera and Ec. kurome (Migita 1984). Genus of economic importance, especially in Japan as important food source for abalone or sea urchin aquaculture (Sanbonsuga 1984). First tissue culture experiments with E. bicyclis were successful (Notoya & Aruga 1990). In E. bicyclis a phlorotannin was identified as a substance with remarkable deodorizing action against methyl mercaptan (Kita et al 1990).

Numbers of names and species: There are 7 species names in the database at present, as well as 1 infraspecific names. Of the species names, 5 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.

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

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

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: 03 June 2015 by Wendy Guiry

Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=36212

Citing AlgaeBase
Please cite this record as:
Wendy Guiry in Guiry, M.D. & Guiry, G.M. 2020. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 26 February 2020.

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