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| Registros recuperados: 12 | |
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| Hoek, C. van den. |
| Recently, I transferred Ectochaete endophytum to Coelodiscus Jao (van den Hoek, 1965). Dr. R. C. Bakhuizen van den Brink (Rijksherbarium, Leiden), however, drew my attention to the fact that Coelodiscus Jao (1941) is a later homonym of Coelodiscus Baillon (1858). The new generic name Jaosaccion is therefore proposed for the ulotrichalean species so far ranged under Coelodiscus Jao. |
| Tipo: Article / Letter to the editor |
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| Ano: 1966 |
URL: http://www.repository.naturalis.nl/record/525001 |
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| Hoek, C. van den; Donze, M.. |
| It is concluded on the basis of data gathered from the literature and of our personal observations, that the algal phytogeographic provinces as assumed by several authors do not exist. The algal floras of NW. Spain and Brittany are richest in species. From these two regions down to the south but far more so up to the north the algal flora gradually changes mainly by species dropping out and being only partially replaced by others. One very obvious floristic discontinuity is not correlated with a discontinuity in the temperaturerange of the surface-water, namely the one along the west coasts of the British Isles. The floristic discontinuity Arctic Europe-Spitsbergen is correlated with a temperature discontinuity. Floristically and as regards... |
| Tipo: Article / Letter to the editor |
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| Ano: 1967 |
URL: http://www.repository.naturalis.nl/record/526047 |
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| Hoek, C. van den. |
| During some trips to several points on the Dutch and French coasts barnacles were collected in order to get an impression of the algal microvegetation perforating into the shells and growing on them. The barnacles were dried or conserved in formaldehyd-solution; they were decalcified in diaphanol. By treating slides with chloriodide of zinc the chlorophyceae could be distinguished from the remaining algae by their cell-walls and starch-grains stained violet and blue. |
| Tipo: Article / Letter to the editor |
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| Ano: 1958 |
URL: http://www.repository.naturalis.nl/record/525367 |
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| Hoek, C. van den. |
| Joséphine Th. Koster entered her service at the Rijksherbarium as an assistant, April 1930, in the midst of the economic crisis. She was engaged as an, unsalaried collaborator, the then current type of position the Netherlands’ State could offer its scientific offspring. When Prof. Dr. H. J. Lam, freshly appointed Director in August 1933, ordered her to start work each morning as early as the salaried staff-members, she resigned from her unremunerative post by 31 Dec. 1933. She then continued, as a guest of the Rijksherbarium, her investigations on the Compositae of the Dutch East Indies, and in 1935 she took her doctor’s degree on the thesis ‘The Compositae of the Malay Archipelago’ at Leyden University. Her promotor was Prof. Lam. In the end the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1967 |
URL: http://www.repository.naturalis.nl/record/524834 |
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| Hoek, C. van den. |
| The Netherlands’ coast being sandy and muddy is not suitable for most algal growth. Dikes, piers and harbour-works replace the rocks elsewhere. The pier at Hoek van Holland is one of these artificial rocky coasts. It has been constructed with basalt blocks and other hard stones, viz. the so called “Nilvoordste steen” and “Doornikse steen”, both from Belgium. The pier projects into the sea about 1350 m. On the southern side it is washed by the mouth of the Nieuwe Waterweg, on the northern side by the North Sea. A little more (fig. 1) up the Nieuwe Waterweg there are several basins enclosed by a dam parallel to the pier and a number of dams at right angles to it, thus replacing the rockpools of natural rocky shores. |
| Tipo: Article / Letter to the editor |
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| Ano: 1958 |
URL: http://www.repository.naturalis.nl/record/525322 |
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| Hoek, C. van den. |
| Coelodiscus endophytus (Möbius) v. d. Hoek nov. comb. — Bulbocoleon endophytum Möbius, 1891, p. 1292—1293. — Endoderma endophytum (Möbius) Huber, 1892, p. 325— 326. — Ectochaete endophytum (Möbius) Wille, 1909, p. 79; Heering, 1914, p. 98; Printz, 1964, p. 204. — Endoderma jadinianum Huber, 1892, p. 322—326. Thallus tubular or saccate, irregularly lobed or plicate, eventually opening and splitting, growing attached to Cladophora glomerata by coalescent endophytic branched filaments, up to 1 cm long and 0.5 cm broad. On cross-section, the wall of the hollow thallus consists of two to three layers; one or two innermost layers of large, rounded or slightly elongate, mostly colourless cells, 30—60 µ in diam., and one, sometimes two, outer layers of smaller,... |
| Tipo: Article / Letter to the editor |
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| Ano: 1966 |
URL: http://www.repository.naturalis.nl/record/525165 |
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| Hoek, C. van den; Flinterman, A.. |
| Cultural and caryological investigations on Sphacelaria furcigera from Hoek van Holland give evidence of a slightly heteromorphic diplohaplontic life-history in this species. A relatively slender (13.5—31 μ) haploid gametophytic phase alternates with a more robust (19—41 μ) diploid sporophytic phase. Female gametophytes form plurilocular macrogametangia at 12˚ C and 4˚ C, male gametophytes form plurilocular microgametangia at 12˚ C and 4˚ C. Zygotes of female macrogametes and male microgametes grow into diploid sporophytes which form unilocular meiotosporangia at 4˚ C. Meiosis takes place in the initials of these sporangia. About 50 % of the spores produced by them grow into male gametophytes, about 50 % into female gametophytes. Propagules are formed at... |
| Tipo: Article / Letter to the editor |
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| Ano: 1968 |
URL: http://www.repository.naturalis.nl/record/524696 |
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| Hoek, C. van den. |
| During his zoological collecting trips to the Antilles Dr. P. Wagenaar Hummelinck also gathered several samples of fresh and brackish water algae, which have been presented to the Rijksherbarium, Leiden. The present paper deals with the Chlorophyta of that collection, with the exception of Enteromorpha. Wagenaar Hummelinck’s localities 1936—1949 have been described in the “Studies on the Fauna of Curaçao”, Vols. 1 (1940), 2 (1940) and 4 (1953). Sta. 76 A has been illustrated in Vol. 1, Plate Vb; Sta. 97 in Vol. 2, Plate IV a; Sta. 500, 382, 63 and 678 in Vol. 4, Plates Ib, IIa, IIb and Va, respectively. The 1955 localities will be described in a “Third List of Localities”, to be published in a forthcoming volume of this series. |
| Tipo: Article / Letter to the editor |
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| Ano: 1959 |
URL: http://www.repository.naturalis.nl/record/524776 |
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| Prud’homme van Reine, W.F.; Hoek, C. van den. |
| Cultural experiments with Entophysalis deusta support Drouet and Daily’s concept of this species as a morphologically highly plastic taxon, showing forms traditionally identified as Entophysalis granulosa, Gloeocapsa crepidinum, Pleurocapsa fuliginosa, and Hyella caespitosa. These results are in accordance with observations on populations forming part of the ‘black zone’ of the upper intertidal belt. It is shown that Drouet and Daily’s taxonomic principles, leading to a broad and more natural concept of this species, are sounder than those underlying Geitler’s Cyanophyceae in which several entities included by them in Entophysalis deusta are treated as species. |
| Tipo: Article / Letter to the editor |
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| Ano: 1966 |
URL: http://www.repository.naturalis.nl/record/524488 |
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| Prud’homme van Reine, W.F.; Hoek, C. van den. |
| Several decalcifying mixtures or aqueous solutions of inorganic or organic acids are generally used for releasing algae growing in the shells of molluscs and barnacles, for instance dilute hydrochloric, nitric, citric, or acetic acid (4), a mixture of nitric acid, chromic acid and alcolhol (1), nitric acid and alcohol (9), chlorine dioxide and acetic acid (diaphanol) (3, 6, 11, 12), and formic acid and formiate (8). For a review see (7). Such mixtures or solutions generate carbondioxide bubbles that more or less disorganise the histological structure of the thallus. They also hydrolyse cell-contents and cell-wall material. Diaphanol and formiate appeared to be relatively useful for conserving the histological structure of the thalli. Recently (5, 10, 13)... |
| Tipo: Article / Letter to the editor |
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| Ano: 1966 |
URL: http://www.repository.naturalis.nl/record/525419 |
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| Hoek, C. van den. |
| Pendant un séjour de trois semaines à Roscoff au mois d’avril 1957, un Sphacelaria stérile était trouvé plusieurs fois dans les grottes et sur les parois verticaux ombragés et sous les surplombs du littoral supérieur qui ne pouvait pas être déterminé avec certitude, mais dont les caractéristiques correspondaient à ceux de Sphacelaria britannica Sauvageau. Il était trouvé fructifiant sur des pierres au pied du vieux quai (côté nord) du port de Roscoff, de sorte qu’on pouvait l’identifier avec certitude. Cette espèce n’a pas été rapportée pour les côtes françaises par Hamel (1931—1939, p. 251); je n’ai pas pu trouver non plus des mentions dans la littérature plus récente. |
| Tipo: Article / Letter to the editor |
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| Ano: 1958 |
URL: http://www.repository.naturalis.nl/record/526308 |
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| Registros recuperados: 12 | |
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