78 



tively. For the purposes of this paper they may very well be discussed 

 together. Both analyses show the production by the plants of an 

 organic acid or acids strong enough to decompose alkali carbonates; 

 and that to some extent salts of this acid or acids, as well as the acids 

 themselves, accumulate on the plants. In both plants this acid organic 

 material is accumulated on the leaves rather than the stems, a situa- 

 tion which would seem more favorable for its being brought into con- 

 tact with the alkali carbonates on the surface of the ground. 



The accumulation of considerable amounts of potassium is again a 

 noteworthy feature with these species. In both cases there is an 

 apparently greater proportion of potassium in the water-soluble por- 

 tions of the stems than in the leaves, when considered in relation to 

 the other elements present; but when considered in relation with the 

 air-dried material as a whole, the amount of potash is about the same 

 in both leaves and stems for each of these plants. 



In the case of the stems of Atriplex hracteosa the conventional state- 

 ment of the analytical results as salts would indicate the presence of 

 calcium chloride as such, and on the stems and leaves of both the 

 Siiaeda iyifermedia and Airiplex hracteosa considerable amounts of 

 magnesium chloride are indicated. That these salts were actuallj^ 

 as such, however, is negatived by the fact that the air-dried 

 did not in any case show the presence of any notably deli- 

 ) t substance on their respective surfaces after being dried in 



T • r • : . The conventional method of statement is again misleading, 

 ' '';^ case of the Disticlilis spicata^ discussed above. 



SUMMARY. 



the facts which have been presented in this paper the follow- 



jlusions seem justified:^ 



at the plant species here considered can make a satisfac- 



)wth on soils containing relatively large amounts of soluble 



,tes. 

 .. i jiat this satisfactory growth is probably due, in large measure 

 at least, to the production and exudation by ^hese plants of consider- 

 able amounts of soluble organic acids capable of decomioosing soluble 

 carbonates, and thus protecting the root crowns from the corrosive 

 action of hj^drolized alkalies. 



3. That it api3ears certain that large quantities of the most valuable 

 plant foods are removed from the soil by these jilants, aiid that in any 

 contemplated use of them, involving their cropping or removal from 

 the soil, this factor merits earnest consideration. 



^Acknowledgment is due Mr. Atherton Seidell for assistance in making the 

 analyses presented in this paper. 



o 



