BOTANY. 547 



in this aiudunt appears unfavorable to tlie j2;r()\vtli and reproduction of the plants, 

 and it is believed that the eoniparatively sudden increase of the carbon dioxid in the 

 air to an extent of 2 or 3 times the present amount would result in the speedy 

 destruction of nearly all our plants. 



The influence of an excess of carbon dioxid in the air on the form and 

 internal structure of plants, J. B. Farmer and S. E. Chandler ( Proc. Roy. Soc. 

 [Loudon'], 70 {1902), No. 4G4, PP- 413-433, figs. 5; aU. in Bot. Centbl., 90 {1903), No. 

 11, pj). 296, 297). — The plants experimented upon as reported in the previous article 

 were investigated by the authors to determine the relative dimensions of the inter- 

 nodes, the average relative area of the leaves, number of stomata i)er unit of leaf 

 surface, anatomical differences in the stems and leaves, and the relative amount of 

 starch and other cell contents in the two series. 



The results are given in detail, from which it appears that an excess of carbon 

 dioxid checks the growtli of the internodes while prolonging the period of growth. 

 The leaf area is more or less reduced by checking the growth of the leaves at an 

 early stage. The absolute number of stomata per unit area of leaf surface is consid- 

 erably increased, although the relative proportion of stomata to the number of epi- 

 dermal cells remains practically constant. The anatomical structure of the leaf tissue 

 is not materially altered. In the stem the xylem areas are less lignified, Init the 

 phloem shows no alteration. As a rule, there is a considerable increase of starch 

 and a diminution of the amount of tannin and crystals of calcium oxalate. No alter- 

 ation could be detected in the roots as a consequence of the increase in the carbon 

 dioxid content of the air. These results are held to differ in a remarkable way from 

 those obtained by Teodoresco (E. S. R., 10, p. 610), but that author compared plants 

 grown in an atmosphere containing carbon dioxid with those grown in an atmosphere 

 which was almost deprived of this source of carbon. 



Investigations in chlorophyll assimilation of leaves, E. Griffon ( Cornpt. 

 Rend. Acad. Sci. Paris, 135 {1902), No. 5, j>p. ,?05-^05).— Experiments are briefly 

 reported on the effect of illuminating the different surfaces of the leaf on its chloro- 

 phyll assimilation. Leaves were placed in flattened tubes, so that the different sur- 

 faces could be subjected to direct and diffuse illumination, and the amount of gas 

 given off determined. Differences were noted for the different surfaces of the leaf, 

 and considerable inequality was observed, the differences seeming to be somewhat 

 dependent upon the thickness of the leaf. In thick leaves, such as the cherry laurel, 

 the proportion of assimilation of the upper and lower surface was as 100 : 48. In 

 thin leaves, such as the maple, the proportion was 100 : 88, and in the case of leaves 

 in which the mesophyll is more or less homogeneous, as in the case of the bamboos, 

 the proportion was 100 : 92. In the case of leaves whose under surface is covered 

 with hairs, as the linden, raspberry, and others, the difference was quite marked, and 

 for such species as Eleagnus, in which the lower surface is covered with a dense cov- 

 ering of scales, the proportion fell to 100 : 36. The results seeni to indicate that the 

 palisade parenchyma of the leaves is adapted to the decomposition of carl)on dioxid. 



The influence of colored light on vegetation, G. T. Grignan ( Rev. Ilort. {Paris'] , 

 74 {1902), No. 16, pp. S88-390). — A review is given of the work of Zacharewicz, in 

 which fruits were grown under colored screens, and of Flammarion's experiments 

 with strawberries and other plants grown under the influence of different colored 

 light. 



The influence of different colored light upon plants, C. Flammarion {Ann. 

 Min. Agr. [France], 21 {1902), No. 2, pp. 395-397).— In continuation of the author's 

 investigations on this subject (E. S. R., 12, p. 909), experiments are reported in which 

 (Tladioli were grown under white, red, green, and blue lights. At the same time 

 the bulbs of Montbretia were grown under similar conditions. The effect of the dif- 

 ferent illuminations is shown in tabular form, from which it appears that the plants 

 are not similarly affected by the different kinds of light. Summarizing his work on 



