Dictyosiphon Greville, 1830, nom. cons.

Holotype species: Dictyosiphon foeniculaceus (Hudson) Greville

Original publication and holotype designation: Greville, R.K. (1830). Algae britannicae, or descriptions of the marine and other inarticulated plants of the British islands, belonging to the order Algae; with plates illustrative of the genera. pp. [i]-lxxxviii, [1]-218, pl. 1-19. Edinburgh & London: McLachlan & Stewart; Baldwin & Cradock.

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Description: Plants mostly epiphytic, occasionally epilithic, attached by a small holdfast, solitary or caespitose, cylindrical, alternately or oppositely branched, solid when young but later becoming hollow, up to 50 cm in height, yellowish to medium brown in color, attenuated toward the apex, polystichous, consisting of 2-3 cell layered medulla and cortical layer. Medulla composed of large roundish colorless thick-walled cells. Cortical layer consisting of cubic or roundish pigmented cells containing several chloroplasts with pyrenoids. Phaeophycean hairs present. Unilocular sporangia scattered on entire thallus, formed among the cortical cells, slightly immersed, irregularly shaped. Plurilocular sporangia not detected on erect thalli. Sexual and heteromorphic life history shown in C. foeniculaceus (Peters 1985). Unispores of the macrothallus negatively phototactic, germinated into branched prostrate filamentous dioecious gametophyte (microthallus) with phaeophycean hairs. Microthalli formed plurilocular sporangia under lower temperature conditions irrespective of day length. Gametes isomorphic, negatively phototactic. Female gametes settled faster and secreted finavarrene as sexual pheromone, and then fused with attracted male gametes. Zygote developed into macrothallus forming unilocular sporangia via protonema. Unfused gametes of both sexes gave rise to macrothalli in the same way as zygotes. Unispore as well as plurispores pear-shaped, biflagellated with longer anterior flagellum, containing a chloroplast with a stigma.

Information contributed by: H. Kawai. The most recent alteration to this page was made on 2015-10-19 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 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, 1 fig., 1 table.

Comments: Distributed widely in the cold and temperate water area of northern hemisphere.

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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=63

Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 19 October 2015. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 24 November 2024