32 BOTANICAL GAZETTE (JANUARY 



have been of value. In a sphagnum substratum all three of the 

 plants produced hairlike roots which attain a length of 5-7 cm . 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 mm , 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,- 1 was led to test 

 this fact by growing the sphagnum in tap water and solutions of 

 CaCO 3 . In one experiment the water in a battery jar was saturated 

 with CO 2 , CaCO 3 was added in excess, and the CO 2 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 3 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: Larioc laricina, Pinus 

 Strobus, Picea Mariana, Betula lutea, Betula pumila, Oocycoccus 

 macrocarpus, O. Oxy coccus, Chio genes hispidula, V actinium corym- 

 bosum, Ledum Groenlandicum, Populus tremuloides. 



