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| Schroevers, P.J.; Voo, E.E. van der. |
| The first record of Sphagnum riparium Angstrom in the Netherlands was made by Meyer in 1946. The present authors mention a new locality of it in the “Peel”, a drained region of raised bog in the southern part of the Netherlands. A description of the material is given and the environment has been analysed. The latter research leads to the following conclusions: 1. S. riparium is found in man-made bog pools, which, originally oligotrophic, by influence of the surroundings have changed into a slightly meso-metatrophic habitat. 2. The species is only found in pools, arranged in more or less extended systems. A light movement of the water may be required. 3. A certain amount of shadow may favour the growth and occurrence of the species. |
| Tipo: Article / Letter to the editor |
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| Ano: 1965 |
URL: http://www.repository.naturalis.nl/record/526695 |
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| Schroevers, P.J.; Roest, A.C.F.. |
| In a shallow pond, dug in an oligotrophic area, but enriched by recreation, a waterbloom of a micro-organism which at first could not be identified was investigated. Cultivation showed a transformation into distinct colonies of Dictyosphaerium pulchellum Wood, which species was repeatedly recorded from the pond before. It might be possible that the observed cells developed from zygotes, but in fixed material collected earlier no indications could be found to state this. During the development of the culture the formation of colonies could be followed. The process starts with the formation of autospores. Division into 4 autospores occurs about 6 times as often as into 2. Deviations of the progress of the process may be explained by desynchronisation of the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1967 |
URL: http://www.repository.naturalis.nl/record/527281 |
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| Schroevers, P.J.. |
| Microthamnion strictissimum Rabenh., recorded as a new species for the Netherlands by Koster (1963), has, however, been found before by Romijn (1923), Beijerinck (1927), and Middelhoek (1950). The related M. kützingianum is known from this country since 1887 (Weber-Van Bosse). The present author mentions 5 new localities in De Peel (a dead moorland region in Noord-Brabant and Limburg) and one in the Bergvennen (Overijsel). The following conclusions have been drawn from the study of the material: 1. In De Peel specimens are found, which doubtless belong to M. strictissimum or kützingianum, but intermediate forms are also met with; a further revision of the genus seems to be necessary. 2. M. strictissimum is ecologically well-defined. It prefers an... |
| Tipo: Article / Letter to the editor |
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| Ano: 1963 |
URL: http://www.repository.naturalis.nl/record/527576 |
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