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case had the plant grown on a firmer substratum. Those found were 

 merely fragments of the tips of the thallus and were thin casts without 

 the markings which are characteristic of the upper surface, and without 

 the rhizoids of the under surface. There was. indeed, nothing to dis- 

 tinguish the casts from those which might have been formed by any mem- 

 ber of the group, except the fact that they agreed in size and form with the 

 unmixed colony of this species which grows immediately above them. 

 Lafayette. Ind., November. 1905. 



