Books and Current Literature. 293 



Chenopodiaceae 14 Mimosaceae 6 Ranunculaceae 4 



Cactaceae 13 Onagraceae 6 Scrophulariaceae. . . . 4 



Papilionacese 12 Amaranthaceae 5 Zygophyllacea* 4 



The following brief summary will be interesting to the botan- 

 ist from the standpoints of taxonomy and phytogeography. : 



Number of plant families 68 



Number of genera 269 



Number of genera common to both hemispheres 126 



Number of genera common to North and South America 58 



Number of southwestern genera 39 



Number of introduced genera 22 



Number of species 449 



Number of southwestern species 264 



Arizona Agricultural 



Experiment Station, 



BOOKS AND CURRENT LITERATURE. 



Vinson, in a recent number of Science, describes the method 

 by which the fruit of a seedling date may be ripened into a per- 

 fect commercial product in less than three days, by simply sub- 

 jecting the sprays of fruit to the vapor of acetic acid. By this 

 process it is expected that dates may be shipped green and after- 

 wards ripened at their place of destination, thus preventing the 

 deterioration on the way which is due to the inversion of the cane 

 sugar in the ripe date. The author finds that the ripening pro- 

 cesses are initiated not only by acetic acid but also by a number 

 of other chemicals. Detailed results of his work will soon be 

 published. 



Molisch, in the Sitsungsberichte of the Vienna Academy, 

 describes experiments in which the buds of Forsythia, Syringa, 

 and various other plants produced new shoots in response to 

 immersion in warm water. As a rule, the same result was not 

 attained by prolonged exposure to an atmosphere saturated 

 with water vapor at the same temperature. The author points 

 out that during immersion in warm water there is not only a 

 raising of temperature, but that a whole complex of other factors 

 is involved, such as interference with respiration, absorption of 



