238 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9 
DESCRIPTION OF PLATES 
Plate XI 
Fig. I . View of one of the four series of pots of experiment V of the soil-culture studies, 
illustrating the difference in vigor of growth between plants receiving different nutritive 
treatment. 
Fig. 2. On the left, a pot containing 5 plants of group A (grown in sand); and on the 
right a pot containing 5 plants of group F (soil highly fertilized with NaNOs) ; experiment 
V of the soil-culture studies. 
Plate XII 
Fig. 3. Crown rust of oats. A rust mycelium exhibiting a very marked tendency 
towards teleutospore production. The first sorus produced by the mycelium (in the center) 
is a uredosorus. The others are teleutosori. Photographed with Zeiss 3.5 cm, microplanar. 
X 24. 
Fig. 4. View of infected leaves of a semi-starved plant and of a richly fed plant of 
soil-culture experiment V, showing larger size of pustules on more luxuriant host plant. 
Photographed with Zeiss microplanar. X 15. 
Fig. 5. Same as figure 4. X 10. 
Erratum 
In the first part of this paper, appearing in the Journal for April, 1922, pp. 183-203, 
on page 188, line 32, and on page 193, line i, for Puccinia Caryophylli read Uromyces 
caryophyUimis . 
