274 MEMOIRS OF THE NEW YORK BOTANICAL (JARDEN. 



scence of any specific substance. Vochting*'-'^' found that flower-buds 

 failed to open, or make full development in Dolichospci-nium Hali- 

 cacabum, Tropaeohcni Lobbianiim and Minmhis Tillingii, and did 

 not open when grown in chambers, the atmosphere of which was en- 

 tirely free from carbon dioxide. That the failure to carry out flower- 

 formation in the usual manner was due to lack of suitable nutrition 

 is not entirely clear in the light of the recent researches of Brown 

 and Escombe''^^ upon the influence of atmospheres containing more 

 than the normal proportion of carbon dioxide. The atmosphere 

 usually contains about 28 parts of carbon dioxide in 100,000, and 

 when plants were confined in ventilated chambers through which air 

 containing 114 parts of carbon dioxide in 100,000 " inflorescence was 

 almost totally inhibited." " With the exception of one or two sickly- 

 looking flowers on the begonias, not a single flower-bud opened on 

 any of the plants of this set." " The plants of Impatiens, Kalanchoe^ 

 and of the darker leaved fuchsias did not even produce flower-buds, 

 whilst in Nicoliana, cucurbitas and lighter leaved fuchsias, the smaller 

 flower-buds which commenced to form were completely shed long 

 before the time of opening." The rate of absorption and use of car- 

 bon dioxide by the plant was found to increase with the proportion 

 of this substance in the atmosphere up to certain limits, but the 

 products of the photosynthetic activity of plants grown in such atmos- 

 pheres evidently could not be handled by the conducting mechanism 

 and general metabolic complex of the plant, for the dry weight of 

 specimens grown in atmospheres richer than the normal in carbon 

 dioxide was less than the average of plants grown in ordinary air. 

 Stems grown under experimental conditions with increased propor- 

 tions of carbon dioxide were composed of shorter internodes, but 

 these members were increased in number so that the plants reached 

 average height, although deviating from the normal stature by the 

 development of a greater number of axillary buds by which the 

 shoots were made more dense in their general aspect. Nothing in 

 the above experimental observations could be found to suggest a 

 direct poisonous action of carbon dioxide on the plant. 



The recent results by Chapin become of direct interest in this 



190 Vdchting, H. Ueber die Abhangigkeit des Laubblattes von seiner Assimila- 

 tionsthatigkeit. Bot. Zeitung, 49 : 113,129. 1S91. 



1^' Brown and Escombe. The influence of varying amounts of carbon dioxide in 

 the air on the photosynthetic processes of leaves and on the mode of growth of plants. 

 Phil. Trans. Roy. Soc. 193: 278. 1900. Abstract in Nature, 65: 621. 1902. 



