76 The Plant World. 



of the plant remains, the author has reached the conclusion that 

 salt marshes in the area under consideration are features of, 

 and an accompaniment to, coastal subsidence, and also that this 

 type of deposit gives a record that can not be disputed, of the 

 date of subsidence and its uniformity. The rate in eastern 

 Massachusetts has not yet been determined, but is probably 

 slow, perhaps less than a foot in a century. 



Mr. F. Y. Coville has rendered a useful service in presenting 

 the results of his experiments in blueberry culture (Bur. PI. Ind. 

 Bull. 193) from which it appears that although the species 

 designated by this name differ fundamentally in their osil re- 

 quirements from all the common cultivated plants, nevertheless 

 even the swamp blueberry may be very successfully grown in 

 the right kind of soil, as for instance Kalmia peat. Regarding 

 the well known fact that the swamp blueberry and certain other 

 plants, as Cypripedium acaule and Azalea nudifora, occur not 

 only in peat bogs but also in sandy upland soil, the author re- 

 marks:" The favorite explanation of this phenomenon among 

 botanists is that these plants are naturally adapted to the drier 

 situation and that in the bog they find a situation of 'physiologi- 

 cal dryness,' or vice versa. While the existence of physiological 

 dryness in peat bogs is not questioned, the explanation that a 

 bog plant finds an upland situation congenial because it is dry 

 certainly will not answer for the blueberry. Its occurrence on 

 these two habitats is dependent on the acidity of both situations. 

 These experiments have shown that no amount of dryness 

 will make a blueberry flourish in an upland soil if that soil is not 

 acid. Of much interest are the observations on the mycorrizal 

 fungus and its presumed role in transforming the nonavailable 

 nitrogen of peaty soils into a form of nitrogen available for the 

 nourishment of the blueberry plant. The effects of partial 

 shading, the necessity of pollinization by an outside agency, 

 improvement by breeding and selection, and methods of propaga- 

 tion are treated in detail. The paper may be taken as the most 

 complete exposition of the biological requirements of this very 

 interesting plant that has yet appeared. 



