12 THE PLANT WORLD. 



indicates: Armeria maritima, 26.68 per cent, (only 1.99 per 

 cent, in the root) ; Aster tripolium, leaves, 43.00 per cent., 

 stem, 47.08 per cent; flowers, 19.10 per cent.; Chenepodiiim 

 maritimiim, 44.06 per cent., stem, 47.08 per cent.* Analyses 

 of the ash of Atriplex canescens, A. polycarpa, and A. Nut- 

 tallii, made nnder the direction of Prof. W. J. Gies, Colum- 

 bia University, show that they contain 9.15 per cent., 9.1 1 

 per cent., and 24.56 per cent, chlorine respectively. The 

 material for these analyses was selected from the zones of 

 the salt spot of which each species is typical. The Atriplexes, 

 therefore, are to be classed among the most marked halo- 

 phytes although A. canescens, and perhaps A. Polycarpa as 

 well, grow also in soils that are apparently free from alkali. 

 A comparison of the results in Wolff's tables of plant analy- 

 ses shows that there is a very general agreement between the 

 relative amounts of such elements as calcium, magnesium, 

 chlorine, potassium and sodium in the soil and in the plant 

 growing on the soil, although the selective power of plants 

 may materially alter this relation. And Nathansohn has 

 shown** that the HCl content of the expressed sap of the 

 sea weed Codium tomentosum is the same as in the surround- 

 ing medium and that CI ions will diffuse into or out of the 

 cells of the plant in accordance with the greater or less 

 density of the ions in the surrounding medium. These facts 

 suggested the possibility that the salt plants which occupied 

 areas, the soils of which are unlike as to salts, might in them- 

 selves vary as to salt content. To test the relative abundance 

 of salts in the three types of halophytes of the salt spot solu- 

 tions were made in a uniform manner which were tested for 

 electric resistance with the apparatus used on the soil solu- 

 tions. The following table summarizes a typical series of 

 experiments. 



♦Schimper, Plant Geography, Eng. Trans., p. 88, cites Wolff's "Ash 

 Tables." 



♦♦Referred to in Role of diffusion and osmotic pressure in plants, 

 Livingston, p. 78. 



