302 



Fig. 39. Lack of potassium. 



/, Defornieil tobacco leaf, resulting from a lack of potassium, with partially split, brown edges: only the 

 veins are still green while the intercostal fields appear discolored yellow to white; 2, Leaf of a normally 

 nourished potato plant; 3, that of one starving for potassium. In this the leaflets stand closer to one anotlier 

 and are curled under. The places drawn in light are yellowish, the intercostal fields are flecked with 

 brown, as also the edges of the leaves; ■/ and 5, leaves of the buckwheat plant with spots which are yellow- 

 ish, then brown, and finallv white. (After Wilf-^RTU and Wimmer). 



