a3 BOTANICAL GAZETTE [JANUARY 
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have been of value. In a sphagnum substratum all three of the 
plants produced hairlike roots which attain a length of 5-7°™. The 
roots are commonly several times branched, very little difference in 
thickness being shown by the several branches. When grown in 
sand the roots are still slender, but the frequency of branching is 
enormously increased. Usually the branching occurs just back of 
the growing tip. The older root ceases growth as the lateral root 
develops. The branch continues for 2-3 ™™, and it also stops growth 
with the formation of a second lateral root. The result of this pro- 
cess is a zigzag root showing root branches which have been succes- 
sively the main root tip. Occasionally several lateral roots develop 
and the main axis is divided. 
(6) The statement that waters containing lime and other mineral 
salts are unfavorable to the growth of sphagnum has gained wide 
circulation in ecological literature. Because of the great abundance 
of lime and magnesia in the waters of this vicinity, I was led to test 
this fact by growing the sphagnum in tap water and solutions of 
CaCO,. In one experiment the water in a battery jar was saturated 
with CO,, CaCO, was added in excess, and the CO, was again 
allowed to pass through the water for thirty minutes. In this solu- 
tion sphagnum was placed, and it has been growing vigorously for 
three months, although watered daily with water containing over 100 
parts of CaCO, to the million. Some of the sphagnum cultures have 
been running for ten months, and show no signs of deterioration. 
Whether the sphagnum of this vicinity has become accustomed to 
the presence of lime, owing to the nature of the soil waters, or whether 
sphagnum is generally able to withstand such conditions, remains to 
be proved. Since the above experiments were performed, I have 
found an account of somewhat similar experiments by WEBER (58), 
the results of which are the same. It would seem, therefore, that the 
presence or absence of sphagnum is not to be correlated with the 
presence or absence of lime. 
(7) Among the plants growing in the bogs of this vicinity the fol- 
lowing have been found to possess mycorhiza: Larix laricina, Pinus 
Strobus, Picea Mariana, Betula lutea, Betula pumila, Oxycoccus 
macrocar pus, O. Oxycoccus, Chiogenes his pidula, wi te corym- 
bosum, Ledum Groenlandicum, Populus tremuloides. 
