ON THE IMPORTANCE OF PHYSIOLOGICALLY 

 BALANCED SOLUTIONS FOR PLANTS 



II. FRESH-WATER AND TERRESTRIAL PLANTS- 



W. J. V. OSTERHOUT 



(WITH SEVEN FIGURES) 



If the facts set forth in the first part 1 of this paper prove to be valid, 

 not for marine plants only, but also for all other kinds, we cannot 

 suppose them to be merely the result of adaptation to a particular 

 environment, but must consider them to be the direct expression of 

 certain fundamental characteristics of living matter. In order that 

 the evidence on this important point might be as complete as possible, 

 a wide range of material was studied. It includes both lower and 

 higher algae, liverworts, Equisetaceae, and several species of flower- 

 ing plants, embracing among the latter both fresh-water aquatics 

 and land plants. The solutions were made up with all the precautions 

 regarding distilled water and purity of salts described in the first 

 part of this paper. The solutions had the same compositions as 

 there described, except that lower concentrations were employed. 

 A control series was always made, in which all solutions were made 

 faintly alkaline. The material was always rinsed in distilled water 

 before being placed in the solutions. The plants were in all cases 

 exposed to fairly bright light, but not to direct sunlight. The tem- 

 perature averaged between 18 and 2OC., and was not subject to 

 much fluctuation. 



ALGAE 



The most extensive series of experiments on algae was made 

 with Vaucheria and Spirogyra. AfoimofVaucheriasessilis, abun- 

 dant in running water, was chosen because it readily gives off zoo- 

 spores when brought into the laboratory. Tufts of this material, 

 washed free from all adhering dirt, were placed in glass dishes and 

 covered with tap water. Glass slides were placed upright in the 

 dishes. On the following morning numerous zoospores were found 



1 BOTANICAL GAZETTE 42: 127-134. 1906. 

 259] [Botanical Gazette, vol. 44 



