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| Smit, Petra G.. |
| At least some of the species of the genus Caltha are polymorphic, showing not only a wide range of intraspecific morphological variation, but also considerable cytotaxonomic differentiation. A number of taxonomic problems are connected with this phenomenon. In a previous paper (Smit, 1967) a survey of the chromosome numbers of 46 Dutch populations was given. Two cytotypes of Caltha palustris were found, 2n = 32 and 2n = 56, respectively, with slight morphological differences and different ecological preferences. |
| Tipo: Article / Letter to the editor |
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| Ano: 1968 |
URL: http://www.repository.naturalis.nl/record/535012 |
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| Smit, Petra G.; Punt, W.. |
| Contrary to Europe, with only one Caltha species, North America has at least three species of this genus. These are the polymorphic C. palustris L., also widely distributed in Europe, the floating aquatic C. natans Pall, and the polymorphic C. leptosepala-biflora group. Two previous papers (Smit 1967, 1968) dealt with taxonomic aspects of C. palustris, that in North America were not essentially different from those of European material. |
| Tipo: Article / Letter to the editor |
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| Ano: 1969 |
URL: http://www.repository.naturalis.nl/record/535214 |
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| Smit, Petra G.. |
| The family of the Ranunculaceae, although a large one (ca. 1200 species) occurring almost throughout the world, is generally regarded as a very natural one. The only genera with a recently more or less disputed position are Circaeaster, Glaucidiutn, Hydrastis, Kingdonia, and Paeonia. The others may at present all be considered to be ‘true’ Ranunculaceae. Various botanists have studied the delimitation of these genera, their affinity and phylogenetic links. Their ideas are often widely divergent. There is no need to go into the subject here, but some opinions on the place in the system of Caltha may be reviewed. |
| Tipo: Article / Letter to the editor |
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| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/534972 |
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| Smit, Petra G.. |
| The family of the Ranunculaceae, although a large one (ca. 1200 species) occurring almost throughout the world, is generally regarded as a very natural one. The only genera with a recently more or less disputed position are Circaeaster, Glaucidium, Hydrastis, Kingdonia, and Paeonia. The others may at present all be considered to be ‘true’ Ranunculaceae. Various botanists have studied the delimitation of these genera, their affinity and phylogenetic links. Their ideas are often widely divergent. There is no need to go into the subject here, but some opinions on the place in the system of Caltha may be reviewed. |
| Tipo: Article / Letter to the editor |
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| Ano: 1973 |
URL: http://www.repository.naturalis.nl/record/525917 |
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| Smit, Petra G.. |
| The genus Caltha comprises approximately 12-16 species growing in wet, marshy places in arctic and North and South temperate regions. The genus in classed in the tribe Helleboreae of the Ranunculaceae. A. de Candolle (1818) subdivided the genus into two sections: Psychrophila and Populago, the distinguishing features being that in the former the calyx is persistent, the auricles of the leaf laminae having upturned to erect appendages, whereas in the latter the calyx is deciduous and the leaves are cordate to reniform. In the section Psychrophila he placed two species of the Southern Hemisphere, the other section including all the species of the Northern Hemisphere. The peculiar leaf characters of the species of the Southern Hemisphere (5-8) are highly... |
| Tipo: Article / Letter to the editor |
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| Ano: 1967 |
URL: http://www.repository.naturalis.nl/record/535089 |
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| Smit, Petra G.. |
| 515 specimens of the polymorphic species Caltha palustris from 55 Dutch localities were studied morphologically and cytologically. Two cytotypes could be distinguished, a cytotype with 32 chromosomes and another with 56 chromosomes. These two cytotypes have slight morphological differences and different ecological preferences which although incompatible in crosses are insufficient for distinguishing separate species or even subspecies. The studies lead us to the conclusion that Caltha palustris is a species with large genecological differentiation in its populations. The intraspecific polyploidy, which could have arisen by mutations, will have enhanced the polymorphism of the species, resulting in series of more or less discontinuous ecotypes with... |
| Tipo: Article / Letter to the editor |
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| Ano: 1970 |
URL: http://www.repository.naturalis.nl/record/526480 |
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