438 
AMERICAN JOURNAL OF BOTANY 
[Vol. io, 
double-maximum curve with a minimum between for water absorption by 
plant tissue in solutions of different hydrogen-ion concentration offers a 
satisfactory explanation for the double-maximum curves found in the 
germination of spores and seeds, the growth of plants, and the infection of 
plants by fungi in media of different hydrogen-ion concentrations. The 
connection between water-absorption and spore germination or seed 
germination, and water-absorption and the growth of plants, is generally 
recognized. Recent evidence seems to indicate that the infection of plants 
by fungi which enter through the unpierced epidermis is due to a pressure 
process. A minimum water absorption would mean a minimum pressure 
and a minimum infection. 
Department of Botany, 
University of Missouri 
LITERATURE CITED 
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