AGRICULTURAL BOTANY. lM 



especial significance of this unusual method of fruiting is held to be a means of pro- 

 tection of the flowers againsl boo much rain and also to protect them and the fruit 

 from excessive heat, the trunks of the trees being usually the portion besl shaded. 

 These plants are also said to have especial devices for protection againsl insects. 



The frost injuries of leaves, II. Solereder ( Centbl. Bakt. [etc.], .'. Abt., 12 1904), 

 No. 6-8, pp. 258-262, figs. 8).- A description isgivenof the anatomical changes caused 

 in apricot and beech leaves by the action <>f frost. 



Physiological drought in relation to gardening, I. B. Balfoi r Plant World, 

 8(1905), No. 1, pp. 1-5). — After discussing the water relationships of plants when 

 growa under natural conditions, t lie ant In >r considers the water requirements of plants 

 under horticultural practice, and states that in no direction has research in recent 

 years provided more valuable data of significance to horticulture than in t hat of water 

 relationship of plants. 



The relation of soils to physiological drought is discussed, after which the author 

 calls attention to a number of gardeners' problems and offers explanations concerning 

 them. Among these may be mentioned the explanation of marsh plants growing 

 in sand, epiphytic orchids grown in pots containing peat, the changed condition of 

 epiphytic plants when grown in greenhouses, conditions of physiological droughl 

 caused by cold, pot cultivation, etc. A proper conception of the explanation of all 

 these phenomena is held to be requisite for the rational cultivation of plants. 



Anthocyanin and its biological significance in plants, L. Buscalioni and 

 (J. Pollacci (Atti 1st. Bol Univ. Pavia, 2. ser., 8 i 1904), pp. 185-511, ph. 10).— The 

 authors present an elaborate memoir on the occurrence and biological significance of 

 anthocyanin. 



After a discussion of pigments and other coloring matters in plants, the authors 

 give an account of the localization of anthocyanin in different parts of plants, its 

 chemical composition, spectroscopic analysis, influence of media, climate, etc., on its 

 formation, the relation of this coloring matter to various physiological activities of 

 plants, pathological conditions, etc. Experiments aie described at Length on the 

 distribution, localization, effect of various physical and other agents on the produc- 

 tion of anthocyanin, etc. 



The investigations are summarized and various hypotheses are offered regarding 

 the role of anthocyanin in plants. A bibliography of nearly 1,000 references to lit- 

 erature is given. 



Investigations on chlorophyll assimilation, (i. Pollacci (Atti 1st. Hot. Univ. 

 Pavia, .'. sir., 8 | 1904 >. pp. 1-66, pis. ■>). — The results of a prolonged series of investi- 

 gations on chlorophyll assimilation and the various factors which determine and 

 modify photosynthesis are given. A considerable list of publications consulted is 

 appended as a bibliography. 



The importance of the removal of the products of growth in the assimila- 

 tion of nitrogen by the organisms of the root nodules of leguminous plants, 

 .1. Golding (Jour. Agr. Sci., / | 1905), No. /, pp. 59-64).— In order to ascertain the 

 rdle of the host plant in the process of nitrogen assimilation the author planned a 

 series of experiments, the main feature of which was the removal of the soluble 

 products of growth in a way similar to that which occurs in nature. This removal 

 was affected by the use of a porous Chamberlain! filter candle fixed in the culture 

 vessel. 



The leaves, stems, roots, and nodules of young bean plants, water extracts of 

 young pea plants, and sterilized extracts of similar plants were cultivated. In the 

 first experiments the plants were simply cut up and bruised in a mortar, the initial 

 infection being provided by the organisms present in the crushed tubercles. In t he 

 later experiments with sterile liquids the cultures were inoculated from pure cultures 

 of the organisms grown on agar. The details of the experiments are given and the 

 amount of nitrogen fixed in each case is shown. 



