Dicranema Sonder, 1845
Lectotype species: Dicranema grevillei Sonder
Currently accepted name for the type species: Dicranema revolutum (C.Agardh) J.Agardh
Original publication: Sonder, G. (1845). Nova algarum genera et species, quas in itinere ad oras occidentales Novae Hollandiae, collegit L. Priess, Ph. Dr. Botanische Zeitung 3(4): 49-57.
Request PDFType designated in: Schmitz, F. (1889). Systematische Übersicht der bisher bekannten Gattungen der Florideen. Flora oder Allgemeine botanische Zeitung 72: 435-456, pl. XXI.
Description: Plants are obligate epiphytes of the woody stalks of the seagrass Amphibolis spp. They grow in clusters from a discoid base and are small (generally <5 cm in length), wirey, terete, and dichotomously branched without proliferations. Carpogonial branches are aggregated around fertile branch apices. Following fertilization the carpogonium appears to fuse to one of the non-differentiated adjacent cortical cells, which forms the nucleus of a small fusion cell from which multiple gonimoblasts radiate thallus-inwardly, fusing with interior vegegatve cells and forming an extensive placenta. Gonimoblast growth appears to halt at the placental stage while a cavity develops by autolysis of adjacent gametophytic cells, following which clusters of gonimoblast filaments arise from the placental surface and grow into the chamber. The cells of this outer carposporophyte layer consolidate into a hemispherical mass on which the large, ovoid carposporangia are produced singly and terminally. An ostiole develops on the side of the fertile axis opposite the site of gonimoblat initiation, but most spore release appears to take place with breakdown of the tissue surrounding the cystocarp. Spermatangia occur in chains of 3 or more. Tetraspsorangia are formed in swollen, subterminal nemathecia that surround the fertile axis. Carposporophyte development in Dicranema is a complex procedure that appears to progress in a series of discrete stages involving much interaction of gametophyte and sporophyte tissue. Kraft (1981) illustrates the process and regards it as arguably the most elaborate and specialized in all the red algae.
Information contributed by: G.T. Kraft. The most recent alteration to this page was made on 2010-10-07 by M.D. Guiry.
Taxonomic status: This name is of an entity that is currently accepted taxonomically.
Most recent taxonomic treatment adopted: Kraft, G.T. & Womersley, H.B.S. (1994). Family Dicranemataceae Kylin 1932: 65. In: The marine benthic flora of southern Australia. Rhodophyta - Part IIIA. (Womersley, H.B.S. Eds), pp. 321-330. Canberra:
Comments: Distribution: The type species was one of the earliest collected Australian marine algae and occurs from near 26 deg. latitude in the west to eastern Victoria and northern Tasmania in the east. The second species, D. cincinnalis Kraft, is even more diminutive and is recorded from South Australia and Victoria.
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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=39915
Citing AlgaeBase
Cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 07 October 2010. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. https://www.algaebase.org; searched on 22 November 2024
