772 THE AMERICAN NATURALIST. [Vol. XXXVIII. 



Part II, 1900) upon the sporocarp, have suggested a somewhat 

 different affinity, and it was thought worth while to look into the 

 evidence carefully, supplementing it by a direct comparison of 

 such material as was available. 



Goebel has called attention to the similarity between the young 

 sporocarp of Marsilia and the fertile leaf-segment of Schizaea. 

 Johnson's studies on the sporocarp of both Marsilia and Pilularia 

 bear out this, and a comparison with Prantl's figures of the 



young sporophytes of Schizaea emphasizes the marked resem- 

 blance between the two (Fig. 5). Johnson does not admit the 

 foliar nature of the sporocarp ; that is, he does not believe the 

 capsule is homologous with the leaf lamina, a view which has 

 been expressed by the writer, and which is supported by most 

 students of the subject. A comparison of the developing fertile 

 segment of the leaf of Schizjea, however, shows that at the 

 time the first rudiments of the marginal sporangia appear, there 

 IS no more trace of a lamina than in a corresponding stage of 

 the sporocarp in Marsilia. In short, the structure of the very 



