Haplodasya Falkenberg, 1897

Holotype species: Haplodasya reinboldii Falkenberg ex F.Schmitz & Falkenberg

Currently accepted name for the type species: Haplodasya urceolata (Harvey ex J.Agardh) M.J.Parsons

Original publication and holotype designation: Schmitz, F. & Falkenberg, P. (1897). Rhodomelaceae. In: Die natürlichen Pflanzenfamilien nebst ihren Gattungen und wichtigeren Arten insbesondere den Nutzpflanzen unter Mitwirkung zahlreicher hervorragender Fachgelehrten, Teil 1, Abteilung 2. (Engler, A. & Prantl, K. Eds), pp. 421-480. Leipzig: verlag von Wilhelm Engelmann.

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Description: Thallus an obligate epiphyte on Cystophora and Carpoglossum. Hemispherical holdfast embedded in host tissue; erect thallus, up to 20 cm long, monopodially branched, radially organized with corticated cylindrical polysiphonous axes with 5 (4 in some short branches or dwarf plants) pericentrals, each segment with a persistent, pigmented monosiphonous branched trichoblast. Surface cortical cells or pericentrals may produce adventitious simple or branched filaments resembling trichoblasts in H. tomentosa but not in H. urceolata (Parsons 1975) where they arise only from proximal cells of trichoblasts or their polysiphonous bases. Polysiphonous indeterminate branches originating by transformation of trichoblasts or similar adventitious filaments. Procarps develop proximally on trichoblasts or adventitious filaments; a 4-celled carpogonial branch and a single sterile cell group attached to the supporting cell. Two connecting cells formed after fertilization, one of which fuses with the auxiliary cell. Spermatangial capitula formed on unbranched trichoblasts or adventitious filaments, with 3 pericentrals per segment the fertile area enveloped by a single layer of spermatangial mother cells and terminated by 1-2 sterile cells. Tetrasporangial stichidia also formed on unbranched parts of trichoblasts and adventitious filaments; without trichoblasts on stichidia; 4 pericentrals formed, the 2nd becoming fertile. Two presporangial and 1 post-sporangial cover cell formed; tetrasporangia arranged in a single longitudinal row.

Information contributed by: R.E. Norris. 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: Schneider, C.W. & Wynne, M.J. (2007). A synoptic review of the classification of red algal genera a half a century after Kylin's "Die Gattungen der Rhodophyceen". Botanica Marina 50: 197-249.

Comments: Subtidal on hosts, Cystophora or Carpoglossum, Western Australia and southern Australian coast east to Victoria. Haplodasya differs from Lophothalia and Doxodasya in 1) formation of tetrasporangial stichidia from trichoblasts rather than polysiphonous ramuli and has no trichoblasts on the stichidium; 2) only 1 pericentral forms tetrasporangia in each stichidium segment; 3) tetrasporangia arranged in a longitudinal row rather than in decussate pairs or in a single row; lateral polysiphonous branches arise from conversion of entire trichoblasts rather than on a proximal branch.

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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=40447

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 29 March 2024

 
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