5io BOTANICAL GAZETTE [December 



kiln-dry peat, the solubility of which in water is very low. The 

 results confirm, however, both an increase in the production of 

 dry matter in plants, and of dry matter relatively richer in the 

 amount of nitrogen, as compared with the percentage in plants from 

 soils lacking peat. 9 



Additional evidence of a similar nature is derived from experi- 

 ments of more recent date with pure cultures of isolated bog organ- 

 isms growing in sterilized solutions of bog water and peat (table 

 IV, nos. 7 and 10), and from the preliminary work upon peat com- 

 posted with the bacterial life from stable manure. They confirm 

 the earlier experiments and also demonstrate the ability of some 

 mycelial bog fungi and the organisms in alder tubercles 10 to increase 

 transpiration and green weight of wheat plants about 200 per cent 

 above that in untreated bog water. Normal appearance is here 

 associated with a uniformly higher absorption of the solution, 

 amount of transpiration, and green weight produced, and with the 

 healthy condition of roots and leaves. The wheat plants in the 

 cultures have the usual osmotic pressure isotonic with about a 

 0.2 to 0.3 normal potassium nitrate solution. Difficulty in 

 absorption and tolerance or the xerophytism in bog plants do not 

 seem to be correlated with high osmotic pressure. 11 



The point of most importance which should be noted in this con- 

 nection is the obvious difference in the water requirements of the 

 plants. Water and its solutes, whether organic compounds or 

 inorganic salts, are as a general rule taken up in a different ratio 

 from that existing in the substratum. The existing differences 

 in the various colloids of cells would naturally tend toward inequali- 

 ties in the amount of water or solutes absorbed and held by the 

 tissues of the different varieties of species; the diosmotic properties 

 of the protoplasmic membrane, differing according to the species 



• Haskixs, H. D., The utilization of peat in agriculture. Massachusetts Sta. 

 Rept., pt. 2:39-45. 1909. 



Lepman, J. G., Report of the soil chemist and bacteriologist of the New Jersey 

 Agricultural Experiment Station. 1910. pp. 188-195. 



10 Spratt, E. R., The morphology of the root tubercles of Alnns and Elaeagnus 

 and the polymorphism of the organism causing their formation. Ann. Botany 26: 

 119-128. 1912. 



ix Fitting, H., Die Wasserversorgung und die osmotischen Drukverhaltnisse 



* 



der Wiistenpflanzen. Zeitschr. f. Bot. 3:209-275. 191 1. 



