Pachychaeta Kützing, 1862
Holotype species: Pachychaeta griffithsioides Kützing
Currently accepted name for the type species: Pachychaeta brachyarthra (Kützing) Trevisan
Original publication and holotype designation: Kützing, F.T. (1862). Tabulae phycologicae; oder, Abbildungen der Tange. Vol. XII pp. i-iv, 1-30, 100 pls. Nordhausen: Gedruckt auf kosten des Verfassers (in commission bei W. Köhne).
Taxonomic status: currently recognized as a distinct genus.
Most recent taxonomic treatment adopted: Hommersand, M.H. (1963). The morphology and classification of some Ceramiaceae and Rhodomelaceae. University of California Publications in Botany 35: -vii, 165-366, 52 figs, 6 photo pls.
Description: Thalli comprised of prostrate and erect (up to ~18 cm) branching systems, polysiphonous and uncorticated. Prostrate branches are of two types, stoloniferous and rhizomatose, the latter having attachment organs which are modified adventitious polysiphonous branches rather than rhizoids. All branches are cylindrical, with 6-16 pericentral cells, the range varying in the 2 species, shape and arrangement of pericentrals differing in the species. Trichoblasts are not formed; lateral polysiphonous branches developed exogenously or adventitiously. Erect branches formed at irregular intervals on stolons, rhizomatous branches also develop at the same place. Exogenous laterals originate on concave side of thallus, the lateral initial opposite the first pericentral cell. Erect branches either unilateral or in a 1/8 spiral sequence; often reduced to rudimentary spine-like branchlets in P. cryptoclada. Reproductive structures on reduced branchlets with spiral arrangement of branchlets on axis, branchlets forming lateral branches on every segment resulting in tufts of fertile branchlets. Procarps formed on 2nd or 3rd basal segment of branchlet, procarp consisting of 4-celled carpogonial branch and 2 sterile cells attached to the supporting cell. One spheroidal cystocarp develops on each fertile branch; they are without an ostiole (Hommersand 1963). Male capitula compound in P. brachyarthra, with cylindrical lobes with sterile tips (Hommersand 1963). Tetrasporangia borne 2 per segment, at close to right angles to one another forming, more or less 2 straight rows; spine-like rudimentary branchlets in 1/4 spiral series on tetrasporangial branch axis.
Information contributed by: R.E. Norris. The most recent alteration to this page was made on 7 Oct 2010 by M.D. Guiry.
Comments: Intertidal to upper sublittoratal, South Africa (Caribbean record is suspect acc. to Hommersand 1963).
Numbers of names and species: There are 3 species names in the database at present, of which 2 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):
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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
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=40824
Please cite this record as:
Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 23 July 2019.