THE NATURE OF THE ABSORPTION AND TOLERANCE 



OF PLANTS IN BOGS 1 



Alfred Dachnowski 



* 



The consideration of measured physical habitat conditions, 2 

 which is desired as a basis for distributional relationships of plant 

 associations, their succession and morphological distinction, and 

 particularly for a theory of physiologically arid habitats, has not 

 rendered clearer the nature of the absorption of plants in bogs and 

 peat deposits. Interest in the study of the absorption and the vary- 

 ing degree of tolerance and resistance of plants growing in Ohio 

 bogs has been coincident with the determination of the quantita- 

 tive nature of the habitat factors, but it has been only through an 

 appreciation of the subordinate value of the physical habitat factors 

 that attention could be given to the special diosmotic properties 

 of the plants and of the substances absorbed, together with the 

 changes which the penetrating substances produce upon the plants. 

 The changes which the substances undergo internally or externally 

 to the absorbing cell or organ are relationships of equal importance 

 in the problem of nutritive metabolism, but a discussion of them 

 cannot be attempted as yet. 



The evidence as to the role of physical and biotic habitat factors, 

 derived from study of bog vegetation in its relations to the sub- 

 stratum, temperature, and evaporation, from consideration of 

 the relation of bog vegetation to the chemical nature of peat soils, 3 

 need not be reviewed here in detail. Tt pointed to something else 

 than merely the atmospheric influences as ecological conditions 

 for the development of bogs and for the selection and growth of 

 plants tenanting such areas. 



1 Contribution from the Botanical Laboratory, Ohio State University. No. ft. 

 Read before the Botanical Society of America at the Washington meeting, 191 1. 



2 Dachnowski, A., The vegetation of Cranberry Island (Ohio) and its relations to 

 substratum, temperature, and evaporation. Bot. Gaz. 52:1-33, 126-150. 1911. 



, The relation of Ohio bog vegetation to the chemical nature of peat soils- 

 Bull. Torr. Bot. Club 39:53-62. 1912. 



503I 



[Botanical Gazette, vol. 54 



