Professor Lang has published the first of a series of communications describing the structure of the Quillwort, Isoetes. This is a curious plant, a distant relation of the Clubmosses (Lycopods), all of whose immediate relations appear to be extinct. This investigation of a familiar but little understood plant promises to provide a thorough explanation of its construction and a sound basis for a comparison of the stock of Isoetes with the Stigmarian bases of the fossil tree-Lycopods, whose morphology has long been a puzzle to fossil botanists.
Miss E. M. Berridge's recent account of the anatomy of the Fagaceæ (Beech family) is of much interest. Her observations lead her to the conclusion that the Amentiferæ (catkin-bearing trees) are not primitive, but derived from plants with large flowers. She finds the Fagaceæ connected by various links with the Rosaceæ.
Several American botanists have published investigations on the stem anatomy of flowering-plants, in which they have attempted to trace the changes that have occurred during evolution, and from which they conclude as others have done from more general considerations, that the tree-habit is relatively primitive in flowering-plants.
Our knowledge of fossil seeds has been augmented by two important contributions. One comes from Dr. Wieland of America, whose researches in wonderfully rich material have added so much to our information on the Bennettitales; he describes yet another type of complex inflorescence, helping to build up our conceptions of the evolution of the flower. The other, by Salisbury, is a most careful and detailed account of some new fossil species of Trigonocarpon, old seeds from the Coal measures which make one realise more profoundly how complex were plant organs even in those days.
Professor Bottomley has carried a step farther his investigations on the fertilising influence of "bacterised peat," i.e. peat acted upon by the bacteria of ordinary soil. In a paper in the Proceedings of the Royal Society on "Some Accessory Factors in Plant Growth and Nutrition," he traces the increased growth of plants supplied with this fertiliser to certain organic substances of unknown nature present only in minute proportions, yet enabling the plants to make use of a larger amount of the food available in the soil. From quantitative cultural experiments he infers that wheat seedlings are able to form a certain limited amount of these substances during germination, from material present in the grain, but that after a time their rate of growth falls off considerably unless further supplies are available from without. These substances are obtained from ordinary soil, but are more plentiful in "bacterised peat" (though not in ordinary peat), so that their presence is due to bacterial activity. Professor Bottomley draws an interesting parallel with the substances that have been found necessary by Dr. Hopkins and others, likewise in minute proportions, for the growth of young animals. The diseases of beri-beri and scurvy have been traced to the lack of similar substances when the diet consists of polished rice or lacks green vegetables and fruit.
In a series of experiments Mr. F. Kidd has thrown new light on the conditions which lead to dormancy of the embryo in ripe seeds, and which must be removed if germination is to take place. Maturation involves a cessation, or at least a retardation, of the growth of the embryo, and this is shown to be the result of the accumulation of carbon dioxide in the tissues, which acts as a mild anæsthetic. In the soil, carbon dioxide is frequently present in considerable amount, especially where manure and other organic matter is being decomposed, or in the deeper layers, and under such conditions the anæsthesis tends to be prolonged and germination delayed. During maturation the accumulation of carbon dioxide is due to the seed-coat becoming impermeable to it. If the seed-coat is removed the embryos, for instance, of peas can readily be induced to continue their growth without any period of rest.
Dr. W. Brenchley, working at Rothamsted with a view to the understanding of the peculiarities of certain natural soils, has found that zinc and arsenic have no stimulative effect on the growth of pea or wheat seedlings, but are toxic even in very minute proportions—a few parts per million—while boron has a small stimulating effect on growth when in very minute proportions, though it also becomes toxic when less diluted.
Knight and Priestley have begun an attempt to analyse the beneficial influence of an electrical discharge on the growth of crops, by examining its influence on the different functions of plants. Beginning with respiration, they find that an electric discharge has no appreciable effect on the rate of respiration until it is powerful enough to raise the temperature appreciably and that then the whole effect is attributable to the rise in temperature.
Professor Ewart of Melbourne has published an impressive account of researches on oxidation by organic and inorganic catalysts. He has studied the nature of the activity of enzymes responsible for oxidation in the Apple, Lemon, Maize, Parsnip, Beetroot, etc., and in view of his results controverts the generally accepted views, first promulgated by Chodat and Bach, that oxidising elements belong to several classes, differing in chemical value and their mode of action.