Assen, Netherlands
Assen, Netherlands

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Van Tooren B.,Van der Helstlaan 19 | Van Westen M.,Podzolhamel 26
Gorteria: Tijdschrift voor Onderzoek aan de Wilde Flora | Year: 2011

The ecological distribution of most Desmid taxa in the Netherlands is poorly known due to taxonomic problems and few taxonomic specialists. An exception, however, is the relatively well-documented genus Micrasterias Ralfs, whose species occur primarily in weakly buffered water bodies. Sixteen species of Micrasterias have been recorded in the Netherlands; with four of them apparently locally extinct and another six (critically) endangered. The main reason for the rapid decline or extinction of these Desmids in the Netherlands is the widespread loss of slightly buffered moorland pools with high internal variation, e.g. variation in vegetation structure and various stages of succession from open water to bogs. Nowadays, several Micrasterias species are restricted in their distribution to quaking bogs in fens.


Van Westen M.,Podzolhamel 26
Phytotaxa | Year: 2015

From the Netherlands, four desmid species are described as new to science: Cosmarium pseudodifficile, Cosmarium pseudoformosulum, Cosmarium pseudoreniforme, and Cosmarium turpiniiforme. Cosmarium jelskii was rediscovered after approximately a hundred years, Euastrum ansatum var. dideltiforme f. elongatum is raised to Euastrum ruzickae and Tetmemorus flensburgii is separated from Tetmemorus brebissonii. Differences with similar-looking species are discussed. In addition, zygospores of Staurastrum pileolatum are depicted for the first time. © 2015 Magnolia Press.


Van Westen M.,Podzolhamel 26 | Coesel P.,University of Amsterdam
Phytotaxa | Year: 2012

From extensive field studies in the Dutch province of Drenthe and comparative literature research it appeared that Penium spirostriolatum var. amplificatum differs from the nominate variety of Penium spirostriolatum not only by its capitate cell ends but also by coarser and more spiralized ridges on the cell wall and by distinctly different ecological demands. Var. amplificatum, found in 23 Drenthian locations, occurred exclusively in samples with pH<5 whereas var. spirostriolatum, encountered in 25 other locations, was found predominantly in water with pH>5 (up to 7.3). Based on their results the authors propose to raise var. amplificatum to species rank: Penium amplificatum stat. nov. © 2012 Magnolia Press.


Van Westen M.,Podzolhamel 26 | Coesel P.,IBED
Gorteria: Tijdschrift voor Onderzoek aan de Wilde Flora | Year: 2010

In the period 2007-2009, the first author encountered a rich desmid flora on wet, often recently sod-cut moorland soils in the Dutch Province of Drenthe. With respect to five taxa the occurrence in the Netherlands was not determined before: Cosmarium obliquum, Cosmarium decedens var. minutum,Xanthidium tenuissimum, Staurodesmus phimus and Spondylosium secedens. Taxonomy and geographical distribution of those taxa are separately discussed.


Van Westen M.,Podzolhamel 26 | Coesel P.,University of Amsterdam
Phytotaxa | Year: 2014

From the Netherlands, three desmid species are newly described to science: Actinotaenium spinosporum (with zygospores), Staurastrum brachiatoides (with zygospores) and Staurastrum quadriradiatum. In addition to that, zygospores of the rather rare species Staurastrum echinatum are described for the first time. Differences with similarlooking species are discussed. © 2014 Magnolia Press.


Coesel P.,University of Amsterdam | Van Westen M.,Podzolhamel 26
Phytotaxa | Year: 2013

From the Netherlands five new or otherwise interesting desmid taxa are recorded. Cosmarium vossenbergense is described as new to science. Of Closterium pronum the zygospore, up to then unknown, is described as an elongate spore furnished with undulate costae. The rare species Closterium pygmaeum, Euastrum pseudotuddalense and Sphaerozosma aubertianum, newly recorded for the Netherlands, are discussed for their taxonomy and geographical distribution. © 2013 Magnolia Press.

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