Holotype species: Pogotrichum filiforme Reinke
Original publication and holotype designation: Reinke, J. (1892). Atlas deutscher Meeresalgen Im Auftrage des Königlich Preussischen Ministeriums für Landwirthschaft, Domänen und Forsten herausgegeben im Interesse der Fischerei von der Kommision zur wissenschaftlichen Untersuchung der deutschen Meere. Vol. 2 pp. [i-iv], 55-70, pl. 36-50. Berlin: Paul Parey.
Taxonomic status: currently recognized as a distinct genus.
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.
Description: Plants mostly epiphytic on Laminaria thalli, attached with a rhizoidal base or a small disc, forming tufts of fine filaments, slightly gelatinous, simple, partly monosiphonous and partly parenchymatous, solid, up to 5 cm or less in length and 200 _m in diameter, yellowish to dark brown. In monosiphonous thalli, cells are barrel-shaped, in polysiphonous thalli inner cells some larger than peripheral cells. Each cell contains several disc-shaped chloroplasts with prominent pyrenoids. Phaeophycean hairs absent. Unilocular and plurilocular sporangia formed on the same or separate thalli, both directly transformed from peripheral vegetative cells, singly or in sori, sometimes continuous. Unispores as well as plurispores normally biflagellated, containing a chloroplast with a stigma. Life histories without sexual generation known in P. filiforme (Pedersen 1978) and P. yezoense (Sakai and Saga 1981). P. filiforme produces only plurilocular sporangia and P. yezoense produces both plurilocular and unilocular sporangia. Unispores as well as plurispores develop into creeping filamentous microthalli with plurilocular sporangia, on which erect macrothalli develop. Copulation of plurispores not observed in either of the species.
Information contributed by: H. Kawai & P. M. Pedersen. The most recent alteration to this page was made on 20 Jun 2014 by M.D. Guiry.
Comments: The fully developed parenchymatous thallus of this genus is unbranched, terete, filiform, and without true hairs. The initial stage of the macrothallus is uniseriate without a terminal true hair. At any developmental stage, any cell of the macrothallus may be transformed into plurilocular, or more seldom, into unilocular sporangia. The transformation is not preceded by vegetative divisions. The microthallus is pseudostreblonematoid, i.e. consists of uniseriate branched filaments. Any cell in the microthallus may also be transformed into sporangia. Three species have been referred to this genus, however, 2 of them are of questionable justification (P. yezoense and P. setiforme). The life history has been studied by Pedersen (1978a), P. filiforme var. filiforme, and by Sakai and Saga (1981), P. filiforme var. yezoense. P. filiforme occurs quite commonly in the North Atlantic as an epiphyte and also, but more seldom, in the northern Pacific.
Numbers of names and species: There are 4 species names in the database at present, as well as 3 infraspecific names. Of the species names, 3 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):
Click here to also show infraspecific names in the list below.
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
Verified by: 20 June 2014 by M.D. Guiry
Linking to this page: http://www.algaebase.org/search/genus/detail/?genus_id=32899
Please cite this record as:
M.D. Guiry in Guiry, M.D. & Guiry, G.M. 2019. AlgaeBase. World-wide electronic publication, National University of Ireland, Galway. http://www.algaebase.org; searched on 20 September 2019.