1906] TRANSEAUBOGS OF THE HURON RIVER VALLEY 31 



four days is shown in -fig. 16. The leaves of the drained warm sub- 

 stratum have an average length of 12.6 mm , of the drained cold 10 mm , 

 of the undrained warm n.4 mm , and of the undrained cold 6.3 mm . 

 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 Poll folia, Betula pumila, and Oxy coccus 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 



