302 MEMOIRS OF THE NEW YORK BOTANICAL GARDEN. 



second growth in darkness. The dried material undergoes an in- 

 verse alteration. The proportion of ash in the fresh material in- 

 creases during the first etiolation and decreases in the second to a 

 point below the normal. When a comparison is made with the dried 

 material, however, the proportion of ash is seen to increase during the 

 first as well as in the second etiolation, in which it about doubles the 

 normal proportion. The small proportion apparent in fresh material 

 of the second etiolation is due to the great increase in the percentage 

 of water present. The increase in the proportion of ash to the dried 

 material during the first and second etiolations is seen to be due to 

 the lessened formation of dried material rather than to any positive 

 increase in the amount of mineral matter carried up into the leaves 

 as an accompaniment or result of etiolation. 



Andre found that an increase of temperature of the higher plants 

 between 15 and 30° C. increased the amount of silica carried up in 

 etiolated shoots. The amount of calcium carbonate was decreased and 

 the quantity of potassium and phosphoric acid remained about the 

 same. The proportion of vasculose among the hydrocarbons was 

 increased. It is difficult to account for the increase in the amount of 

 such an insoluble substance as a result of higher temperature and 

 increased transpiration.""^ 



Interesting comparisons are afforded by the data obtained by 

 Karsten ^'^* with seedlings of Phascohis mnlt/Jforus, which were allowed 

 to grow 15-20 days in the light and others 25 to 30 days in darkness. 

 By reason of the longer period of development in darkness the total 

 weight of the etiolated plants was much greater than it would be if 

 taken at the same age as the normal examples. The relative com- 

 position of the separate organs is shown in the following tables : 



Proportion of Dried Material in Seedlings of Phaseolus multi- 

 Jiorus AFTER Karsten. 



Hjpo- ist 2d and 3d Coty- 



Leaves. cotjl. Internode. Internodes. Roots. ledon. Average. 



Normal 15,878 16,646 13,090 12,100 8,379 21,554 15,502 



Etiolated 16,959 6,668 8,731 8,194 7>509 i7>574 ",43i 



^""See Andr^, G. Action de la temperature sur I'absorption minerale chez les 

 plantes etiolees. Compt. Rend. 134: 668-671. 1902. 



^o* Karsten, H. Die Einwirkung des Lichts auf des Wachstum der Pflanzen. 

 Jena. 1870. 



