194 



very well be simply due to the driving off of imprisoned gas. 

 The respiration curve lags behind the temperature curve from 

 an hour to an hour and a half. Even in bright sunlight there 

 is still a considerable evolution of COo ; at least when the temper- 

 ature is above 40° C. It is well known that in the gas interchange 

 succulents in general show a correspondingly lower absorption 

 of oxygen than evolution of carbon dioxide. This is especially 

 true of the older joints while the younger ones seem to behave 

 more like ordinary plants in regard to the CO2/O2 ratio. But 

 external conditions affect the relative amounts of gases involved. 

 In general at higher temperatures the ratio is more nearly i/i, 

 while at lower temperatures the carbon dioxide evolution rapidly 

 decreases, though the oxygen consumption remains nearly 

 stationary. This part of the work is being done by Miss M. E. 

 Latham and a large amount of data has been secured but not 

 yet reduced for comparison. Opuntia versicolor was mainly 

 employed because it happens to be especially favorable for 

 experimental purposes, but other forms were used in part. 

 The work has been partly carried on in New York and partly 

 at Tucson, Arizona. 

 Meeting adjourned. 



B. O. Dodge, 



Secretary. 



NEWS ITEMS 



It is stated in Osterreichische Botanische Zeitschrijt (May) that 

 Professor Dr. Hans Molisch, director of the Plant Physiology 

 Institute at the University of Vienna, has been invested with 

 the Order of the Iron Crown. 



C. R. Orcutt, of San Diego, California, sailed for Mazatlan, 

 Mexico, July 2, 1913, and plans to make botanical collections 

 during the season in Lower California. 



The following descriptive floras have just been issued by Dr. 

 J. K. Small: Flora of the Southeastern United States: Second 

 Edition, revised and enlarged. Flora of Miami: Contains de- 

 scriptions of the seed-plants growing naturally in the Everglades, 



