Dilophus J.Agardh, 1882

Holotype species: Dilophus gunnianus J.Agardh

Currently accepted name for the type species: Dictyota gunniana (J.Agardh) I.Hörnig, R.Schnetter & Prud'homme

Original publication and holotype designation: Agardh, J.G. (1882). Till algernes systematik. Nya bidrag. (Andra afdelningen.). Lunds Universitets Års-Skrift, Afdelningen for Mathematik och Naturvetenskap 17(4): 1-134, 3 plates.

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Description: Thalli erect, attached by a rhizoidal holdfast or by robust, terete stolons, up to 40 cm long, dichotomous or becoming irregularly laterally branched, complanate, undulate or rugose, branches 1-28 mm broad, surface proliferations in some species numerous. Growth initiated by a single elliptical cell at each branch apex, transversely oriented to the thallus axis, slightly protruding to slightly depressed. Cortical cells monostromatic, 3-5 cells overlying each medullary cell in transverse section. Medullary cells in 1-7 layers in the central portion of the branch and 2-8 layers at the branch margin. Cortical cells with numerous discoid chloroplasts. Scattered hair tufts present. Sporangia solitary or in small groups, scattered on both thallus surfaces, down the central portion of each branch, or in the concavities of undulate or rugose thalli, or in elliptical sori formed around hair tufts. Sporangia ovoid to pyriform, 120-150 mm high when mature, with one or two basal stalk cells. Gametophytes dioecious. Oogonial sori (single oogonia in D. marginatus) scattered across both thallus surfaces leaving a sterile margin, or in the concavities of undulate or rugose thalli. Oogonia tightly packed in rows within sori (except D. marginatus), extending above the thallus surface with one stalk cell. Antheridial sori scattered across both thallus surfaces leaving a sterile margin, or in the concavities of undulate or rugose thalli, often becoming confluent, whitish, standing high above the thallus surface, bordered by 3-5 rows of elongate sterile cells. Antheridia with one stalk cell and many tiers of locules.

Information kindly contributed by J. A.. Philips and R. J. King but may now be outdated.

Taxonomic status: This name is currently regarded as a synonym of Dictyota.

Gender: This genus name is currently treated as masculine.

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.

Comments: Southern Europe, Mediterranean Sea, Morocco, Australia, Japan, Pacific Coast of Mexico, Carribean Sea.

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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=33775

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 23 February 2021. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 01 October 2022

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