19"] DACHNOWSKI—BOG PLANTS 507 



described in earlier papers. 



made 



bog water from the central (cranberry-sphagnum) station on 

 Cranberry Island at Buckeye Lake, Ohio. All experiments were 

 made in duplicate series. Paper-covered "Mason" jars were 

 used containing 500 cc. of untreated bog water. The following 

 selected series in tables I to III is especially suggestive and typical. 

 The tables show at a glance which of the varieties is the more 

 efficient in counteracting the effects of injurious organic compounds. 

 Not only the relative transpiration quantities but also the morpho- 

 logical effects as shown by the general appearance of roots and leaves 

 bear out the observation that the rate of entrance of water is as 

 nigh and higher than the transpiration rate. The evaporating 



power of the air during several of the experiments was relatively 

 high. 



Especially in bog water of greater toxicity than that of the 

 date in the above series, the plants were in strong contrast to each 

 other. The rate of growth varied considerably according to 

 the amount of transpiration and to the supply of available water. 

 The decreased permeability of the plasmatic membrane of the 

 root-hair cells favored their efficiency in selective absorption and in 

 growth. When the rate of transpiration decreased, the root tips and 

 the tops made but slight growth. The roots were discolored for 

 some distance from the tip, appeared gelatinous, and not only their 

 surface but the meristematic tissue seemed injured, inhibiting the 

 formation of new laterals. The leaves were short and unfolded 

 imperfectly. At the beginning of the experiment the roots of the 

 stronger plants were able to counterbalance the injurious action 

 to a slight extent; light brown insoluble bodies appeared deposited 



upon the surface of the roots. 



bog 



roots remained white. Invariably, however, the toxicity was 

 lessened most in plants whose ability to counteract the harmful 

 effects was most pronounced. The plants functioned less readily, 



diminished 



terial products increased. 



A characteristic behavior became evident in the increase of green 

 weight of the plants in the dilute solutions, and in the observation 

 that this effect was far from being uniform in all the cultures. The 



