1917] AGRICULTURAL BOTANY. 821 



So far no cases of hybridlty have been observed in which a species of the white 

 oak group has interriossed with a species of the red oali group. 



The anatomy of woody plants, E. C. Jeffrey {Chicago: The University of 

 Chicago Press, 1917, pp. X+478, pi. 1, figs. 507). — In this booii the author treats 

 of the anatomy of vascular plants, with special reference to its historical 

 and experimental aspects. In former standard works upon this subject the 

 anatomy of existing forms is treated, but the author of the present work sup- 

 plies many paleobotanical and developmental data that are fundamentally im- 

 portant for an understanding of the evolution of plant organization. A chapter 

 on anatomical technique is given that may be used as a guide to the prepara- 

 tion of material for study. 



Ecology and physiology of the red mangrove, H. H. Bowman {Abs. in 

 Science, n. scr., 46 (1917), No. 1184, p. 245). — A report is given of an examina- 

 tion of the microscopic structure of the various tissues of the red mangrove, 

 the material having been collected in the Gulf of Mexico along the lower 

 Florida Keys. I^articular attention has been paid to the presence of intercel- 

 lular stone cells and to the occurrence of tannin cells. The physiological rela- 

 tions of transpiration and absorption of these plants growing in sea water and 

 all dilutions of it, as well as in fresh water, have been studied. 



The author has deduced the law that the transpiration of these plants varies 

 directly as the concentration of the medium. It was also found that there is a 

 definite relation between the amounts of sugar and tannin In the hypocotyls at 

 different stages of growth of the plants. 



The chemical basis of regeneration and geotropism, J. Loeb {Science, n. 

 ser., 46 (HUl), No. 1179, pp. 115-llS).— In continuation of the author's investi- 

 gations on Bt-yopliyllum (E. S. R., 37, pp. 324, 325), additional information is 

 given by which it is shown that the rate of geotropic bending of horizontally 

 placed stems of B. calycinum, if an apical leaf is attached to the stem, increases 

 with the mass of the leaf. The author believes that the phenomena of geotrop- 

 ism are due to the chemical mass action, probably of the common nutritive 

 materials circulating in the .sap, and they are apparently of the same nature as 

 the growth of dormant buds, which is also due to a mass action of the same 

 substances. 



The effects of acids and salts on blocolloids, D. T. MacDougal and II. A. 

 Spokhu {Science, n. ser., 46 {1917), No. 1185, pp. 269-272).— In continuation of 

 investigations on what the authors term biocolloids (B. S. R., 37, p. 32.5), a 

 report is given of the effects of various acids, alkalies, salts, and their various 

 combinations in stimulating growth. 



Anesthesia and respiration, A. R. C. Haas (Science, n. ser., 46 (19/7), No. 

 1193, pp. 462-464). — A preliminary account is given of investigations on the 

 effect of anesthetics upon respiration, from which the author concludes that 

 when Laminaria is exposed to the action of anesthetics in sufTiciont concentra- 

 tion to produce any result there is an increa.se in respiration. This may be 

 followed by a decrease if the reagent is sufRciently toxic, but no decrease was 

 observed with low concentrations which were not toxic. 



The measurement of light in some of its more important physiological as- 

 pects, D. T. MacDotjgai. and H. A. Spoei[r {Science, n. ser., 45 (1917), No 

 1172, pp. 616-618).— The results are given of a test of the photoelectric cell de- 

 veloped by Elster and Geitel, comparisons being made with thi^ Smillisonian 

 pyrheliometcr. 



The authors state that the sodium cell connected with a suilal)lo portublo 

 galvanometer offers many advantages for the measurement of light intensities 

 321)50°— 1,8— No. 9 3 



