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| Registros recuperados: 36 | |
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| Jacobs, M.. |
| The practice of citing collections made in institutional series by the letters of that series instead of by the collector’s name (e.g. FB 23435 instead of Aquilar & Valderrama FB 23435) led, with the publication of so many Identification Lists, to the dishing out of an alphabet soup that many a botanist or curator of collections may find hard to digest. In itself, the system of collecting in long institutional series is an excellent one, permitting great economy in space when collections are to be cited. The oldest series seems to be the KB-one, dating from about 1870, established by Scheffer, followed early in this century by the BS and FB series, established by Merrill. A good number-stamp may have contributed much to the success and consistency with... |
| Tipo: Article / Letter to the editor |
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| Ano: 1967 |
URL: http://www.repository.naturalis.nl/record/532854 |
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| Jacobs, M.. |
| Juglandaceae represent a characteristic northern hemisphere family, in the New World going south to Central America (Mexico, Costa Rica, Guatemala, Panama, Cuba, Hispaniola and found S of the equator as fas as c. 30° S, absent from Africa, and overstepping the equator also in the Malaysian region where Engelhardia extends to Java and New Guinea. This distribution shows a remarkable resemblance with that of the Fagaceae-Castaneae which though absent S of the equator in the Americas, occur in Africa in the Mediterranean part only, and though rather well represented as far as New Guinea are also absent in Australia and the Pacific islands. A noteworthy detail of this parallel is that although both are well represented in the Himalayan region and the... |
| Tipo: Article / Letter to the editor |
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| Ano: 1960 |
URL: http://www.repository.naturalis.nl/record/532539 |
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| Jacobs, M.. |
| These small structures in nerve axils at the underside of leaves have given food to various theories and have been nonetheless in phytographic and taxonomic neglect almost from the beginning. That was in 1887, when the Swede A.N. Lundstroem published an extensive paper, in which he explained domatia as structures intended to accommodate mites – hence the word acarodomatia – which latter would in turn benefit the plant by cleansing the leaves from fungus spores. Lundstroem arrived at this hypothesis on the strength of ideas current in that time, about the existence of symbiotic relations between ants and plants; it was in the heydays of teleology. A closer investigation left little of the illusions about mutual benefit between ants and plants, but such... |
| Tipo: Article / Letter to the editor |
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| Ano: 1965 |
URL: http://www.repository.naturalis.nl/record/533503 |
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| Jacobs, M.. |
| The preparation of botanical drawings is a craft in its own right, and furthermore, draughtsmen are human beings. Even these simple truths are trodden down by the taxonomist who during a final hour hands the draughtsman a bundle of specimens and some hasty indications. Naturally the result is anguish and confusion. Let us therefore add some observations to improve the situation. First: a botanical artist looks at plants with a different eye from the taxonomist – that’s why he is an artist and not a scientist. Fortunately, some overlap exists, where the two can meet. |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/532856 |
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| Jacobs, M.. |
| Plant species protection seems a popular concept nowadays, which leads to the preparation of Red Data Lists, and of sheets for recognition. Such an approach may be sensible in civilized temperate countries with a poor flora widely known; in the humid tropics it is out of the question. There are too many species, and neither books nor people are available to identify them, not to speak of implementation. Besides, dealing with species as isolated entities easily creates the impression that protecting such species would be of any help, to the neglect of the only effective way of conservation: wholesale protection of primary ecosystems. The latter concept, however, is difficult to convey to the public; it is too complex to create a lasting, vivid impression.... |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/533250 |
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| Jacobs, M.. |
| It is noted with some surprise that in none of the well-known floras of the Netherlands and in general of the floras of Europe and North America, the times of fruiting of the plants are regularly indicated. Knowledge of fruits in general seems to be in a backward state as compared with the attention paid to flowers and their biology. It is remarkable that sometimes chromosome numbers are recorded while such easily observable data as fruiting time are neglected. This omission limits the usefulness of floras, if fruits are wanted for identification, demonstration, or propagation, and if times are to be set for weed control. If flowering and fruiting occur in markedly different periods, the fruiting stage seems seriously under-represented in herbaria. Since... |
| Tipo: Article / Letter to the editor |
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| Ano: 1969 |
URL: http://www.repository.naturalis.nl/record/527795 |
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| Jacobs, M.. |
| ”Look, these are the modern trees”, Kostermans remarked, pointing to some concrete piles lying near the Forest Research Institute. None of the participants could have missed the sad impression of a moonscape around Kuala Lumpur, which tells of the construction boom in Malaya. ”In Thailand, timber production is nose-diving”, said the Director General of Forestry over the dinner table, ”in the Philippines, nose-diving!” In Malaya, where in the mid-1960’s the government decided to convert the carefully managed forests into oil palm plantation, it has been discovered that no more timber may have been left by the mid-1980’s. So it was none too soon to amass and review the available knowledge on Dipterocarpaceae with an eye on management of the timber resource.... |
| Tipo: Article / Letter to the editor |
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| Ano: 1981 |
URL: http://www.repository.naturalis.nl/record/532952 |
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| Jacobs, M.. |
| Now that at the Jakarta Forestry Congress it was announced on the behalf of the Indonesian government that a target area has been set to conserve 5% of the land area, eventually to be increased to 10%, the time has come to indicate how these areas are to be allocated. Botanical arguments are available as a guidance; they are drawn from established sources, including experience from work at the Rijksherbarium. A number of points are here given. 1. In Malesia, it is usually possible, clearly to distinguish between primary forest: rich in species, balanced as an ecosystem, complex, fragile, different from place to place, in which rarity of species prevails, slow in regeneration, irreplaceable within any foreseeable amount of time, and secondary forest: poor... |
| Tipo: Article / Letter to the editor |
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| Ano: 1979 |
URL: http://www.repository.naturalis.nl/record/533352 |
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| Jacobs, M.. |
| A. F. G. Kerr (1877—1942) worked in Siam between 1902 and 1932, originally as a doctor, later as government botanist. He made large botanical collections in Siam and surveyed the whole of that country. Our knowledge of the flora of Siam is mainly based on his collections (now completely represented at Kew and in the British Museum), which formed the materials for the Florae Siamensis Enumeratio. A sketch of his life and career is given, also a bibliography, including special publications devoted to Kerr or to his material and details about his collections; by means of an Itinerary the date can be found of any Kerr number as well as the locality with approximate longitude and latitude, and by means of a list originally prepared by Kerr himself and here... |
| Tipo: Article / Letter to the editor |
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| Ano: 1962 |
URL: http://www.repository.naturalis.nl/record/526109 |
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| Jacobs, M.; Sleumer, H.; Steenis, C.G.G.J. van; Hou, Ding. |
| Foxworthy and Symington published revisions of the dipterocarp family for the Philippines (11 genera, 52 species) and Malaya (14 genera, 168 species) in 1938 and 1943 respectively. From 1926 till 1961 van Slooten published revisions of several genera for Indonesia, but knowledge of the largest genera, Shorea and Hopea, and of the island with the greatest number of species, Borneo, remained defective. Plans were developed by the Forestry Departments of Sarawak, Brunei, and Sabah, to fill the gap in a coordinated effort, of which this book is the first substantial result. A first precursory paper with new species appeared in Gard. Bull. Sing. 19 (1962) 253—319, a second, with taxonomic and nomenclatural discussion in vol. 20 (1963) 229—284. A Manual for... |
| Tipo: Article / Letter to the editor |
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| Ano: 1966 |
URL: http://www.repository.naturalis.nl/record/526274 |
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| Jacobs, M.. |
| Loss of species is the key issue of conservation. Contrary to misuse of land which is visible to anybody with eyes to see, the issue of extinction is sly, treacherous, and open to clear perception only for experts. It touches on quality, and reaches far out in time: hard things to grasp for non-biologists. Thus an extra responsibility devolves on those who are in a position to know and to speak. The value of the genetic resource base has been set forth in e.g. the book by O.H. Frankel & E. Bennett, Genetic resources in plants (1970), and in the BIOTROP symposium edited by J.T. Williams e.a., South East Asian plant genetic resources (1975); Myers adds many striking facts: half the prescriptions in the U.S.A. contain a drug of natural origin. The cardiac... |
| Tipo: Article / Letter to the editor |
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| Ano: 1980 |
URL: http://www.repository.naturalis.nl/record/533059 |
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| Jacobs, M.. |
| This is a taxonomic revision of the genus Capparis in South and Southeast Asia, Malesia, Australia, and the Pacific. In this area, four sections are distinguished: 1. sect. Capparis, monotypic with C. spinosa, 2. sect. Sodada, monotypic with C. decidua, 3. sect. Monostichocalyx in a new circumscription containing most of the species formerly included in sect. Eucapparis, with about 65 species in the area under revision, 4. sect. Busbeckea, with 12—14 species in all. Of the 79 species recognized, 7 are new, viz. C. cataphyllosa, cinerea, koioides, monantha, pachyphylla, rigida, and rufidula, and 2 are elevated from varietal to specific rank, viz. C. annamensis (C. grandiflora var. annamensis Baker ƒ.) and C. pranensis (C. thorelii var. pranensis Pierre ex... |
| Tipo: Article / Letter to the editor |
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| Ano: 1964 |
URL: http://www.repository.naturalis.nl/record/525093 |
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| Jacobs, M.. |
| Reviewing the conservation situation in Indonesia, we see that concern for animals outweighs that for plants. Sumatra with its richer fauna of large mammals, is better cared for than Borneo with its richer flora*. Too often in the reports, a forest is called a forest, to the neglect of the amazing diversity among the lowland primary rain forests. The absence of botanical expertise beyond the surface is evident throughout, and but occasionally regretted. In view of the great species diversity, and of the fact that this is located in primary vegetations, for animals of nearly all groups as well as for plants, plant conservation clearly comprises at least half the conservationist’s job, in a humid tropical forest region like Malesia. A botanist’s contribution... |
| Tipo: Article / Letter to the editor |
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| Ano: 1977 |
URL: http://www.repository.naturalis.nl/record/532826 |
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| Jacobs, M.. |
| Allen, Caroline K. (1904-1975) Student of Lauraceae, mainly American but also of SE. Asia and New Guinea, on the Arnold Arboretum staff from 1933 to 1948, later in New York Botanical Garden, where, when the Flora Malesiana in 1968 suddenly was in difficulties, she made considerable efforts to save the project. Obituary Note in J. Arn. Arb. 56 (1975) 264. Bailey, F.M. Australian botanist who in 1879-1915 collected many fungi in Queensland, and wrote a number of papers on them. A list of these and whereabouts of his material given by S.L. Everist & L.J. Alcorn in Taxon 24 (1975) 44. |
| Tipo: Article / Letter to the editor |
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| Ano: 1976 |
URL: http://www.repository.naturalis.nl/record/533280 |
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| Jacobs, M.. |
| Gynostemma hederifolia (Decne) Cogn. in D.C., Monogr. Phan. 3: 916, 1881. (“hederaefolia”). — Sicyos hederifolius Decaisne in Nouv. Ann. Mus. Hist. Nat. Paris 3: 450, 1834. KANGEAN Island (N. of Bali): Gua Peteng, 1 M alt.; Backer 26948 (BO), 15-III1919, ♂, filaments connate up to the top, leaves far more densely puberulous than in the next specimen. |
| Tipo: Article / Letter to the editor |
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| Ano: 1954 |
URL: http://www.repository.naturalis.nl/record/526077 |
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| Jacobs, M.. |
| Take almost any profile diagram of rain forest and it reveals you the neglect: nothing but trees. Even in Flora Malesiana* the manner of their climbing is not always indicated. Foresters regard them as weeds and persecute them systematically (see FOX 1968), which subjects them to extra dangers beyond the ’normal’ forest devastation. This makes them perhaps the most threatened life form amongst plants. Yet it is good to remember that two of the main climber families, Menispermaceae and Piperaceae, contain an extraordinary variety of interesting chemical substances (see HEGNAUER in the reference list). For this same reason it is risky to drink water from Menispermaceae trunks, as can be done by holding up a fresh-cut piece of 1-1½ m (Piperaceae are... |
| Tipo: Article / Letter to the editor |
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| Ano: 1976 |
URL: http://www.repository.naturalis.nl/record/532767 |
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| Heel, W.A. van; Jacobs, M.; Bakhuizen van den Brink, R.C.. |
| This study is a full-sounding prelude to the fundamental work on the morphology of inflorescences, which is being prepared by Prof. Dr. W. Troll of Mainz. All inflorescences in Valerianaceae are understood as modifications of one basic form, the thyrse. It is gratifying to note that forms of inflorescences, described in systematical works as for instance 1) capitate or interruptedly spicate (Plectritis), 2) compound dichasium, dichotomous throughout (cymoid Valeriana spp.), or dichotomously branched inflorescence (Valerianella), 3) ‘rispig bis fast trugdoldig’ (Phuodendron), in reality all are variations on one theme, the decussate mono-, to pleiothyrse, i. e. a simple to compound inflorescence with a racemous primary axis and cymous lateral axes. The... |
| Tipo: Article / Letter to the editor |
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| Ano: 1962 |
URL: http://www.repository.naturalis.nl/record/525793 |
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| Registros recuperados: 36 | |
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