Number Of Botanists Research Articles

Dolomite flora of the Baetic Ranges glades (South Spain)

The vegetation growing on special types of rocks has long attracted the attention of botanists and ecologists. In this respect, interest in serpentine soils has led to the publication of a number of monographs on their flora and vegetation. The high levels of heavy metals, in particular of Ni, and the low proportion of Ca/Mg are generally held responsible for the severe restrictions limiting flora development on this kind of rocks. Although researchers have also studied other types of unusual bedrocks such as gypsum outcrops, little work has been done on dolomites. This is surprising because dolomites share certain features with serpentines (they are both rocks rich in Mg). This paper deals with the flora peculiar to the dolomites of the Baetic Ranges, one of the richest territories in Europe as far as flora is concerned. A number of botanists with experience in the study of this very particular flora have joined together to make a list of the plants peculiar to the dolomites. Our catalogue includes 144 species with a variable degree of “dolomitophily”, the score of which ranging from 1 to 3, the maximal value. A comparison of the taxonomical spectrum of this catalogue with the one found in territories where dolomites are dominant or with other areas of serpentines reveals that there is a given deviation or bias in favour of some families. A similar comparison between biotypes also leads to the observation that, as usually happens on ultramafic rocks, hemicryptophytes tend to be dominant on dolomites. In addition, we show that the proportion of Ca/Mg catalogued for different kinds of soils could be a key element in explaining the restrictions which dolomites and serpentines impose on plants. In dolomites this proportion shows an intermediate position (2.19) between soils derived from limestones (11.30) and serpentines (0.84) in the study area.

Floristic changes in vascular plants in the British Isles: geographical and temporal variation in botanical activity 1836–1988

The temporal and geographical variation in the history of botanical recording in the British Isles between 1836 and 1988 has been reconstructed from literature, herbarium, and field records, and related to the number and distribution of botanists. The number of botanists increased steadily to the 1930s and then five-fold after the Second World War, and is a consistent proportion of the local population. The amount of variation in the literature, assessed from the number of pages published, number of publications, and number of floras, has changed from a low rate between 1836 and 1880, to twice that between 1890 and 1940, and increased steadily to 1988. The number of herbarium specimens collected was also low up to the 1870s and then increased three-fold between 1870 and 1914, decreased between the World Wars, increased in the 1950s, and then decreased as conservation concerns came into play. The number of field records, now on computer, has risen dramatically since the 1930s, especially associated with major recording projects. The Botanical Society of the British Isles (BSBI) Monitoring Scheme data show a strong relationship between the number of hours spent recording at a site and the number of species recorded. The production of literature, collection of herbarium specimens, and field records also vary geographically, being concentrated in the areas in which botanists live. General patterns of recording activity are presented from a combination of the data that follow the general trends shown by the sources. There has been an increase in recording activity, with a low level between 1836 and 1870, followed by a large increase, peaking between 1890 and 1910, followed by decreases during the World Wars, with a recovery between, and a sustained increase since 1950. There is a clear trend from a high recording activity in south-east England to low levels in Scotland and, especially, Ireland, high levels being associated with the main population areas. Temporal and geographical variations in recording activity need to be taken into account when assessing floristic change. © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society, 2006, 152, 303–330.

Moisture and seed carbonization

In recent years the multidisciplinary approach of modem archeology has involved an increasing number of botanists in the recovery, identification, and interpretation of seeds from archeological excavations. These seeds are frequently carbonized. This is particularly true of tell archeology of the Middle East, where usually the concern is the origin and early development of agriculture. In many reports and discussions that treat this subject, the size of carbonized grains from various sites is used to support species or wild from cultivated form determinations. Also carbonized modem forms have been used as reference collections. Concern about relatively small size differences being given appreciable weight in such diagnosis has led to this study of the effect of moisture percentage at carbonization on the size of carbonized grain. Two lots of 10 seeds each of Triticum dicoccum Schrank., T. manococcum L., T. aestivum L., Hordeum vulgare L., and H. distichon L. were adjusted to 11 and 15 per cent moisture.2 Test seeds were carbonized by heating on an asbestos pad for ten minutes. This is thought to be a rough equivalent to grains accidentally dropped into an open fire by site occupants. It was apparent that the lower moisture percentage resulted in carbonized grains more representative of unaltered grain. Table I shows that in every case the length of the grain was shortened, but at 11 per cent moisture the grains were wider following carbonization whereas at 15 per cent they were narrowed. Although more tests with other moisture percentages and other methods of carbonization could

Nomenclature of Fungi

Everyone who uses scientific names may be affected by rules of nomenclature. Mycologists get along surprisingly well with their nomenclature, considering the small amount of effort most of them have given to the formulation of rules for their guidance. A review of some of their nomenclatural problems, and suggestions for a few possible interpretations, revisions, or additions to the rules may, it is hoped, prove useful for discussion; especially since the adoption in 1930 of the type method necessitates reconsideration of much past procedure. The International Rules of Botanical Nomenclature, first adopted at Vienna in 1905, were based on de Candolle's Lois of 1867. These rules covered many of the fundamental problems of nomenclature of all plants. Fungi were not specifically considered. The Brussels Congress in 1910 revised the rules and added (evidently from proposals by Saccardo (1), who did much to keep mycological nomenclature on a fairly even keel, and by a group of mycologists (2)) the articles now numbered 57 and 20, and three or four recommendations, all applying definitely to fungi. This second edition of the rules, published 1912, was followed by the third (the present) edition printed in 1935 which, as regards fungi, has practically no change from the second except the addition of Recommendations VI and VII and a list of proposed nomina generica conservanda. The Congress at Amsterdam in 1935 did not pass alterations specifically affecting nomenclature of fungi. Meanwhile certain workers had done valuable work for nomenclature in developing the American Code. Mycologists could, if they wished, formulate their own rules of nomenclature (as was recommended by a number of botanists at Vienna), but I presume the majority would now vote to continue to follow, after emendation, the rules used by other botanists.

CHANGES IN INTERCELLULAR RELATIONSHIPS DURING THE GROWTH AND DIFFERENTIATION OF LIVING PLANT TISSUES

CHANGES IN INTERCELLULAR RELATIONSHIPS DURING THE GROWTH AND DIFFERENTIATION OF LIVING PLANT TISSUES

THE AREA OF THE INTERNAL EXPOSED SURFACE OF DICOTYLEDON LEAVES

THE SIGNIFICANCE of an internal aerating system and internal exposed surface of foliage leaves has been emphasized by a number of botanists. Stahl (I894), Barnes (1910), Haberlandt (1928a), and Bower (1930) have commented on the importance of this interior moist surface. Several investigators, including Nius (1931) and Takenouchi (1933), have measured the volume of the intercellular space in the leaves of a number of species. Barnes (1910) estimated the internal surface of a hypothetical leaf by analogy. Wlodek (1923), working with Trifolium praetentse, calculated the surface of single palisade cells by measuring their length and diameter, and counted the number of palisade cells per unit area; but he did not calculate the exposed surface of this tissue. This study was undertaken to develop a method for the measurement of the internally exposed surface of dicotyledon foliage leaves, and to determine the extent of this physiologically important area for a number of species. The writer wishes to express his thanks to Professor R. B. Wylie, who suggested the problem, for his assistance throughout the work, and for the use of his slides from which most of the material has been drawn; to Dr. J. A. Yarbrough, who loaned his slides of Bryophylzlum; and to Professor R. P. Baker, of the Department of Mathematics, for checking the method.

Maximum values of osmotic concentration in plant tissue fluids

The observations of a number of botanists have shown that extremely high concentrations may characterize plant tissue fluids, especially when the plants1 occur in a highly saline substratum. To Fitting2 belongs the credit of first demonstrating that extremely high osmotic concentrations are found in some desert plants,3 although Drabble and Lake4 and Drabble and Drabble5 had preceded him in showing the fundamental relationship between environmental conditions and the osmotic concentration of plant tissue fluids.As early as 1902 Cavara reported cryoscopic determinations on saps of high concentration6 and in 1905 gave results in full7 for a large series of determinations made at Cagliari. His maximum values were found in the sap of halophytes growing in localities where the concentration of the soil solution progressed with the advance of the season. He reports freezing point depressions of 7.25° in Obione portulacoides, 7.48° in Salicornia fruticosa, and 7.25° to 8.50° in Halocnemum strobilaceum. His deter...

Certain Violet Names

rather copious literature of violets which for several years past has occupied much space in several botanical journals of New York and Boston must have been unsatisfactory and even dull reading to as many botanists-they are very many, and scattered all over the country-who are interested in violets in the field, as nature there presents them; also I doubt that any considerable number of botanists, of whatever degrees of proficiency in knowledge of the plants, have found pages of guesses about hybrid origins, and high sounding theorizings about Mendelian laws, able to hold their very serious attention. By way of variety there is now given us a paper of considerable length on some aspects of the violet question that to the writer of the paper seem to have been too long neglected. Its leading points are nomenclatorial. This paper is from the facile pen of Mr. Eugene Bicknell of New York, and of course is far as possible from being dull, or uninstructive.' Nevertheless, the man of the facile pen, if proceeding in the name of science, may well be advised to pause, now and then, look up a page of some old volume-or one not so old-and see that his pen tells always the exact truth; for nothing else has permanent place in any science. On the matter of Viola obliqua the first statement of my friend is that The name seems first to have into the modern light in the Illustrated Flora. It seems to have been entirely forgotten here, that the name V. obliqua had emerged into the modern light as early as i 886-ten or eleven years before Mr. Bicknell's date of the emergence-in the Botanical Gazette, the man who presented it to the botanical public being 1 Viola obliqua Hill, and other Violets. Bull. Torr. Bot. Club, vol. 40, pp. 26I-270. June, I9I3.

The Conception of Species as Affected by Recent Investigations on Fungi

THE fiftieth anniversary of the foundation of the American Association is a fitting occasion for a retrospective view of the different branches of science represented in our Society, and one would be glad to hear, from the lips of some botanist who was present at the first meeting of the Association, an account of the changes which have been brought about in the methods of botanical study and research, and of the progress which has been made in North America during the past half-century. Fifty years, however, is a long time in the life of any individual, and of those who in i848 were young, or comparatively young, even the most favored could hardly be expected .to retain their scientific activity in i898. On glancing over the list of members in i848, one sees the familiar names of a number of botanists, including Ashmead, J. W. Bailey, Barratt, Jacob Bigelow, Buckley, Dewey, Emerson, Engelmann, L. R. Gibbes, Gray, B. D. Greene, Edward Hitchcock, Oakes, Olney, Pickering, Thurber, Torrey, and Tuckerman. Not one of these leaders of American botany in their day remains to tell us of the Association in its infancy and to trace its development with the vividness which personal experience alone can supply. It would be scarcely fitting in me to attempt to give a genera] sketch of the part which botany and botanists have played in the life of the Association; nor, remembering the review of recent investigations in botany presented by Prof. Marshall Ward at the meeting in Toronto last year, is it desirable that I should encroach on the ground so thoroughly and so interestingly covered by him. I may, however, on this occasion, be permitted to say a few words on a single question on which opinions have changed very much during the last fifty years,

A New and Easy Method of Studying British Wild Flowers by Natural Analysis

THIS work indicates a very large amount of labour on the part of the author; whether the labour has been altogether well applied is another question. For the field botanist whose sole object is to determine the name of a wild flower it will no doubt be useful in assisting him to make out at least the order and genus, for beyond this it does not pretend to go. No botanist will be disposed to depreciate the value of field botany and of the study of critical species, which often leads to further study of some of the great questions connected with the life of plants. There is no doubt that species-botany had been exalted a quarter of a century ago to a far too prominent place by English workers, and had been much too exclusively followed, to the disregard of morphological and especially of physiological work. The inevitable reaction has set in, and is now perhaps at its height, when the number of botanists who have an accurate acquaintance with our British flora is extremely small. As an introductory work for those who are desirous of increasing this number, Mr. Messer's book may be recommended, always provided that the student does not imagine that it will materially help him in his study of the structural and genetic affinities of the different families of plants. The graphic illustrations are novel in design, and will no doubt help to impress the meaning of the technical terms on the beginner. Some few errors should not have been allowed to pass in a work bearing the date of the present year. Among these is the reference of Selaginella selaginoides to the genus Lycopodium, and the complete suppression of Selaginellaceæ as a British order of vascular cryptogams.