1906] TRANSEAU—BOGS OF THE HURON RIVER VALLEY 31 
four days is shown in jig. 16. The leaves of the drained warm sub- 
stratum have an average length of 12.6 ™™, of the drained cold 10 ™™, 
of the undrained warm 11.4™™, and of the undrained cold Ga, 
Internally, the leaves show a reduction in the intercellular spaces and 
in the size of the cells in the case of the plants grown on the undrained 
cold substratum, when compared with those of the warm drained 
condition. 
(4) In another series of experiments with plants of Larix four to 
five years old practically the same results were obtained. There 
were the greatest number and length of leaves and branches produced 
in the case of the drained warm substratum. The smallest and 
shortest leaves and branches were produced by the undrained cold 
substratum. 
Experiments with Ledum Groenlandicum, Chamaedaphne caly- 
culata, Andromeda Polifolia, Betula pumila, and Oxycoccus macro- 
carpus have failed to produce satisfactory results. This is believed 
to be due to the shortness of the time under which they were under 
cultivation. The plants were brought from the bogs in the late 
autumn and placed in cold frames over the winter. About the 
beginning of March they were brought into the greenhouse, and 
after a few days planted in the warm and cold, drained and undrained 
boxes, previously described. They have grown vigorously, but the 
differences noticeable may not be correlated with the four conditions. 
The cranberry has shown the greatest amount of plasticity, but this 
could not in all cases be correlated with the environment. If these 
plants can be kept under known conditions for two or more years, it 
is probable that they will yield valuable results. 
(5) In order to test the effect of mineral soils, and the ability to 
withstand the presence of large quantities of calcium and magnesium, 
specimens of andromeda, cassandra, and cranberry were grown in 
Sandy loam and sand. They were watered daily with tap water. 
The cultures were started in the autumn of 1902, and produced 
vigorous vegetative shoots during the summer of 1903. They failed 
to bloom, however, and although they are growing well at this time 
(June 1904), they have again failed to bloom. This may be in part 
due to the warm plant-house conditions. The experiment was 
originally started to observe the changes in the roots, and in so far 
