Study of Spirogyra nitida. 



209 



largely of salt water forms. Fucoid plants were analyzed 

 by Godechens,* and his results are given in the preceding 



tablet 



A comparison of the ash of these aquatic plants, Fucus 



and Spirogyra, one a salt-water form, the other growing in 

 fresh water, is in several respects, interesting. The sodium 

 content of the ash is in both cases higher than the potas- 

 sium, and this is even more exaggerated in Spirogyra than 

 in sea forms. Chlorine attains a percentage of 17.23 in 

 Laminaria, but in Spirogyra we have 24.24 per cent. It is 

 exceedingly difficult to account for the unusually large 

 quantity of silica, considering the soft and almost gelatin- 

 ous consistence of the plant. The amount is even greater 

 than we find in many hard, wiry land plants. Sulphuric 

 acid is considerably less in Spirogyra than in Fucus, and 

 phosphoric acid is in very small quantity. The magnesia 

 here falls below the magnesia content of Fucus, likewise 

 the lime ; but, on the other hand, iron and alumina are 

 much higher. 



We have in Spirogyra a plant which, though inhabiting 

 fresh water that contains essentially the same constituents 

 as the soil through which it flows, yet differs essentially in 

 its ash composition from the land plants, and approaches 

 closely to the sea plants in its high sodium and chlorine 

 content, and its small amount of potash. 



This great similarity to the salt water types led to a care- 

 ful search for bromine and iodine, but these elements could 

 not be detected. 



*Von Gorup-Besanez has analyzed Trapa natans and finds for it an ash 

 content as given in this table. (Chem. Pharin. Centralblatt, 1861.) 



Both iron and silica, in this analysis, are extraordinarily high, 

 t Ann. d. Chem. und Pharm., (1854) Vol. 54. P- 35 1 - 



