to the Plant Cell. 
519 
indicated by the fact that Becquerel was able to germinate spores of 
Hypmim velutinum on potassium-free solutions, but not spores of A trichum 
undulatum . 
The results of my experiments also show that potassium is intimately 
connected with the formation of carbohydrates, and that the lack of starch 
is not simply due to a pathological condition, because the chloroplastids 
remained normal for two months, and even increased in numbers. Evidently 
the sub-minimal amount of potassium was sufficient for the manufacture 
of the proteids necessary for the formation of plasmatic material. This 
phase of the cell’s activity will be treated more fully in succeeding 
paragraphs. 
The relation between potassium and starch formation was also studied 
by cultivating prothalli of Gymnogramme sulphured upon the surface of 
Fig. i. Effect of absence of potassium on cells of Moss protonema. A. Filament 
from a complete culture-solution. B. Filament from a culture-solution lacking potas- 
sium. Drawn with aid of a camera lucida. Same scale of magnification used in 
both cases. 
nutrient solutions. On April 15 I made cultures in solutions lacking 
potassium. In part of them sodium had been substituted in an amount 
equal to the potassium taken out, in others neither sodium nor potassium 
was present. Spores were also placed in dishes of full nutrient solution, 
and in dishes of distilled water. At the expiration of eighteen days, all 
the spores except those in distilled water had germinated and grown out 
into short filaments. In the distilled water cultures there were no evidences 
of growth beyond the formation of a few rhizoids. At the end of thirty- 
three days the prothalli in all solutions lacking potassium were much alike. 
At the end of three months there was noted a slightly better growth in the 
