PREFACE 



Applied research on coal has revealed the fact that there is a dearth 

 of fundamental information regarding the nature of the original plant 

 material from which the coal was derived. It is therefore necessary to 

 carry forward a parallel program of fundamental studies whose results 

 should give new concepts that will make applied research even more 

 productive. 



The present paper represents an important contribution to the 

 knowledge of spores and to the relationship between certain types of 

 spores and certain kinds of trees that contributed to the mass of vege- 

 tation from which the coal beds were derived. 



Among the constituents of coal there are certain plant tissues that 

 endure better than others the changes, severe compaction, and other 

 solidification effects of the transformation of plant material into bitu- 

 minous coal. Even in the compressed solid material of the coal in Illinois, 

 such tissues or organs can be found so little altered from their original 

 appearance that they can be readily identified. Also, because of their 

 relatively great resistance to oxidation by chemical reagents, it is possible 

 to isolate them completely from the rest of the coal so that they can be 

 examined and photographed. The most interesting of these forms are the 

 plant spores, which may make up a large percentage of the mass of a coal 

 and hence definitely affect the property of such a coal, and which are also 

 valuable as a record of the forms of vegetation that contributed to the 

 coal bed. The present paper is concerned mainly with the investigation 

 of certain parts of the kinds of plants of which the coal beds are composed. 



The spores vary considerably in their outer form and appearance 

 because of differences in shape and differences in the kind of ornamenta- 

 tion. Shape and ornamentation have been used by paleobotanists as a 

 basis of elaborate and complicated form-classification of spores. This is 

 largely because of the uncertainty as to the identity of the spores in terms 

 of the parent tree. 



For the purpose of relating spore varieties to definite plants, it is 

 fortunate that Illinois coal beds have yielded several important deposits 

 of fossilized peat in the form of coal-balls. These coal-balls are petrified 

 masses of peat material which is preserved essentially in the condition 

 in which it existed in the peat deposit before the overlying strata were 

 deposited. Calcite was deposited in the open cell spaces and in all other 



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