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| Registros recuperados: 13 | |
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| Gadella, T.W.J.. |
| In a previous paper (GADELLA, 1961) I suggested that the basic chromosome number of the Loganioideae might possibly be x = 6. The chromosome number of Anthocleista djalonensis Chev. (2n = 60) was in accordance with this supposition. Further investigations in the Loganiaceae, however, are highly desirable. This paper deals with the chromosome numbers of 7 species of Loganiaceae. The following data might contribute to a more complete knowledge of the relationships between the genera and species of the Loganiaceae. |
| Tipo: Article / Letter to the editor |
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| Ano: 1962 |
URL: http://www.repository.naturalis.nl/record/534920 |
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| Gadella, T.W.J.. |
| A. DE CANDOLLE’s (1830) treatment of the genus Campanula lists 137 species. Many new species were described since, so that the total number of species should be estimated to be at least twice that number. A new monograph of the genus is, therefore, highly desirable (CLIFFORD CROOK, 1951). Any classification into subgenera and sections, based on herbarium studies, is bound to meet considerable difficulties on account of the great uniformity among many floral characters of the various species. Cytological information may prove very valuable in order to arrive at a modern classification of the species within the genus. |
| Tipo: Article / Letter to the editor |
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| Ano: 1962 |
URL: http://www.repository.naturalis.nl/record/535195 |
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| Gadella, T.W.J.. |
| Few cytological data are available of the Loganiaceae. Its subfamily Buddleioideae, often considered a separate family, is a well-defined group, as far as could be concluded from the chromosome number. On the other hand, nothing can be said with certainty of the other subfamily, the Loganioideae, because the available data are still insufficient. Hitherto, the chromosome numbers of the following seven species of Loganioideae, studied by MOHRBUTTER (1936) and Moore (1947), are known: Gelsemium sempervirens 2n = 16 (MOORE, 1947) Strychnos laurina 2n = 24 (MOHRBUTTER, 1936) Strychnos nux-vomica 2n = 24 (MOHRBUTTER, 1936) Strychnos sansibariensis 2n = 24 (MOHRBUTTER, 1936) Spigelia marilandica 2n = 48 (MOORE, 1947) Fagraea fragrans 2n = 12 (MOHRBUTTER, 1936)... |
| Tipo: Article / Letter to the editor |
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| Ano: 1961 |
URL: http://www.repository.naturalis.nl/record/535228 |
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| Gadella, T.W.J.. |
| The author reports the occurrence of Veronica hederifolia L. (2n = 54) and of Ornithogalum umbellatum L. (2n = 27, 2n = 45) on the West Frisian Wadden island Vlieland. The pentaploids of O. umbellatum flower early and are many flowered, the triploids (2n = 27) are few flowered and flower later. The very rare apomictic heptaploid (2n = 63) cytotype of Hieracium pilosella L. has been found on the Vuurboetsduin near the village Oost-Vlieland. Hieracium peleterianum Mérat and the hybrid with H. pilosella have been recorded erroneously from Vlieland (MENNEMA & VAN OOSTSTROOM, 1975); both are only recorded from Terschelling. |
| Tipo: Article / Letter to the editor |
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| Ano: 1976 |
URL: http://www.repository.naturalis.nl/record/526804 |
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| Welzen, P.C. van; Gadella, T.W.J.; Maas, P.J.M.; Daly, D.C.; Mori, S.A.; Jørgensen, P.M.; Obermüller, F.A.; Kjellberg, F.; Rønsted, N.; Chantarasuwan, B.; Lut, C.W.J.. |
| Tipo: Article / Letter to the editor |
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| Ano: 2012 |
URL: http://www.repository.naturalis.nl/record/525008 |
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| Gadella, T.W.J.; Raamsdonk, L.W.D. van. |
| Nieuwe vindplaatsen van Hieracium peleterianum Mérat. Tot dusverre werd het Schellings havikskruid (Hieracium peleterianum) alleen aangetroffen op Terschelling en wel in het gebied tussen Formerum en de Tweede Duintjes van de Boschplaat. Een groot aantal exemplaren werd in augustus 1982 gevonden tussen paal 8 en het gebied van de Noordvaarder op een grazig pad door de duinen ter hoogte van paal 7. Dit betreft een nieuwe vindplaats in een uurhok, waarvan de soort nog niet bekend was. Ook werd bij Formerum aan Zee aan de rand van de Formerumse heide een nieuwe, flinke groeiplaats ontdekt in een uurhok, waarvan de soort overigens reeds bekend was. De grote vindplaats ten zuiden van het Hoornse bos is door bouwactiviteiten aldaar helaas verloren gegaan. |
| Tipo: Article / Letter to the editor |
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| Ano: 1982 |
URL: http://www.repository.naturalis.nl/record/527690 |
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| Gadella, T.W.J.. |
| Since our knowledge concerning the time of fruiting of various Angiosperms is very limited, JACOBS (1969, 1970) recently recommended this subject to the attention of amateur-botanists. The present author is of the opinion that also attention should be paid to the study of the absence of ripe fruits. Various causes may be responsible for this aspect: spatial isolation of the sexes in dioecious species (Mercurialis perennis, Stratiotes abides), interspecific hybridization ( (Violahybrids), triploidy (a.o. Stellaria graminea) and predominance of vegetative reproduction (a.o. in Ranunculus ficaria and some strains of Potentilla anserina). |
| Tipo: Article / Letter to the editor |
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| Ano: 1971 |
URL: http://www.repository.naturalis.nl/record/526438 |
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| Gadella, T.W.J.. |
| 1. The chromosome numbers of 10 species of the genus Viola in the Netherlands were determined. 2. Viola riviniana has various chromosome numbers: 2n = 35, 40, 45, 46, 47 (most often 2n = 40). 3. It was not possible to find a correlation between the external morphology and the various chromosome numbers in V. riviniana. 4. Despite the variability of V. riviniana it proved impossible to divide the Dutch material into subspecies. 5. Some differential characters of V. riviniana and V. reichenbachiana are described. 6. V. canina is not variable in cytological respect in the Netherlands. 7. V. calaminaria is not related to V. lutea but to the V. tricolor complex. |
| Tipo: Article / Letter to the editor |
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| Ano: 1963 |
URL: http://www.repository.naturalis.nl/record/535226 |
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| Gadella, T.W.J.. |
| Hieracium peleterianum Mérat subsp. peleterianum is reported from the West-Frisian Island of Terschelling. The plants were found in 12 different localities in the eastern part of the island. The plants studied turned out to be diploid (2n=lß), sexual and selfincompatible. The presence of hybrids (2n=27) between H. pilosella L.(2n=36) and H. peleterianum Mérat (2n=lß) could be demonstrated near Formerum. The hybrid (H. X longisquamum Peter) is completely sterile but spreads vegetatively. The same hybrid can be produced artificially. In most artificial hybrids the diploid H. peleterianum was the pollen-parent, the reciprocal cross did not usually result in the formation of hybrids. The pentaploid form of H. pilosella (which reproduces agamospermously) failed... |
| Tipo: Article / Letter to the editor |
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| Ano: 1981 |
URL: http://www.repository.naturalis.nl/record/527854 |
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| Gadella, T.W.J.. |
| Mercurialis perennis L. is very rare outside the Calcareous District of the Netherlands. Two very small groups of plants have been found near Rhijnauwen (Bunnik, prov. Utrecht) and one near Middachten (Rheden, prov. Gelderland). In both cases only female plants were found. Cytological studies demonstrated that the plants from Rhijnauwen are tetraploid (2n=84), those of Middachten triploid (2n=63). |
| Tipo: Article / Letter to the editor |
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| Ano: 1974 |
URL: http://www.repository.naturalis.nl/record/527592 |
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| Registros recuperados: 13 | |
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