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| Coesel, P.F.M.. |
| The bogs and broads situated in the NW corner of the province of Overijssel contain a rich desmid flora. Some species rare in or hitherto unrecorded for the Netherlands are discussed. The occurrence of a number of species with a predominantly arctic-alpine distribution, viz. of Cosmarium anceps, C. holmiense var. integrum, C. speciosum, and C. crenatum, is rather striking. These species live, in the area studied, atmophytically among bryophytic vegetation in mesotrophic quaking bogs. Also notable is the common occurrence of the not very well known species Cosmarium insigne in the tychoplankton of many lakes, particularly in those with well-developed stands of Stratiotes abides. |
| Tipo: Article / Letter to the editor |
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| Ano: 1974 |
URL: http://www.repository.naturalis.nl/record/526830 |
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| Coesel, P.F.M.; Hoogendijk, E.M.G.. |
| The Desmidflora of the Mosterdveen (a complex of small fen soaks in the Netherlands province of Gelderland) provides a good example of a microphyte cenose characteristic of an oligotrophic type of water (as described by BEIJERINCK, 1926), which has in the meantime become very rare. The most typical indicator species found in the Mosterdveen are Cosmarium ralfsii Bréb., Micrasterias jenneri Ralfs, Euastrum crassum (Bréb.) Kütz., and Xanthidium armatum (Bréb.) Rabenh. Some species whose occurrence and distribution in the Netherlands is not so well known, partly owing to their problematic taxonomy, are discussed separately. |
| Tipo: Article / Letter to the editor |
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| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/526414 |
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| Coesel, P.F.M.. |
| Subsequent to a previous publication (COESEL, 1974), an additional number of noteworthy records of desmids from the NW corner of the province of Overijssel is reported. The complex of Holocenic lakes and peatbogs of that area increasingly proves to be the richest site of desmids in the Netherlands at the present time. It is especially the very shallow, mesotrophic pools in quivering bogs which have repeatedly yielded records of species new for the Dutch desmid flora (such as Cosmarium hornavanense var. dubovianum, C. quasillus, and C. subbroomei). It is to be regretted, however, that there are clear indications of a depauperisation of the tychoplanktonic desmid flora owing to a deterioration of the waterquality. Some species in particular, such as... |
| Tipo: Article / Letter to the editor |
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| Ano: 1975 |
URL: http://www.repository.naturalis.nl/record/527799 |
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| Coesel, P.F.M.; Kooyman-van Blokland, H.. |
| Near Staverden (province of Gelderland) there is a moist heath where a calcareous loam is found mostly very close to the surface. In the past the loam was exploited in several places, which resulted in an unevenness of the terrain and in a number of gradients (wet-dry, rich in humus — poor in humus, lime-rich — poor in lime). The more or less permanently waterfilled loam pits contain a rich desmid flora characteristic of a mesotrophic environment. Among the taxa recorded from this locality four are new for the Netherlands, viz., Staurastrum sexcostatum var. productum, Cosmarium annulatum, C. decedens var. apertum, and C. notabile. Of common occurrence in more oligotrophic shallow depressions filled with Sphagnum found at other sites in the area are, e.g.,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1976 |
URL: http://www.repository.naturalis.nl/record/528075 |
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