ARTICLES 



73 



taken to select those that resembled each other in 

 external characters as nearly as possible. 



In addition to the surprisingly high transpiration of Salt- 

 cornia indicated by these experiments, the higher transpiration 

 of the crimson plants as compared with the green plants is of 

 particular interest especially in view of the various opinions 

 which have been put forward with regard to the physiological 

 role of anthocyan in plants. 



Before passing on, it may be remarked that this method 

 of measuring transpiration, the estimation of the loss of water 

 by finding the decrease in weight, is the one which commended 

 itself as being likely to yield the best results ; the use of the 

 various kinds of potometer was precluded owing to the small 

 size and succulence of the plants. 



The experiments described above were followed by others 

 of a more exact nature. 1 



Shoots of the red and green varieties of Salicornia annua, 

 of Snceda maritima, and, for comparison, Mercurialis annua, 

 a typical mesophyte, were set upright in shallow tins of melted 

 wax which, on solidifying, supported the plants and also sealed 

 the cut ends, so that any loss of water must have been through 

 the intact aerial parts. The tins and their contents were 

 weighed and placed in the open all under exactly the same 

 conditions. 



During the course of the experiment the tins were periodi- 

 cally weighed, and, when the plants had wilted, the areas of 

 the exposed parts were estimated. The following table (IV) 

 sets forth the results : 



Table IV 



1 Delf, Ann. Bot. 25, 485, 1911. 



