142 BOOKS AND CURRENT LITERATURE 



which the sporophyte of the Marattiaceae, especially that of Kaulfussia, 

 resembles that of the Ophioglossaceae. 



In Part III, the origin and relationship of the Eusporangiatae, Gamp- 

 bell points out that, in the absence of adequate evidence from fossils, 

 we are dependent on comparative study of living forms in determining 

 the phylogenetic position of the Eusporargiatae. Starting from the 

 assumption, made for reasons given in his "Mosses and Ferns," that the 

 sporophyte of the Eusporangiatae is descended fom that of a liverwort- 

 like form, he chooses Anthoceros as the nearest living form to this ances- 

 tral liverwort. He then points out the essential similarity of the sexual 

 reproductive organs of Anthoceros and the Eusporangiatae and compares 

 the late fruiting, persistent sporogonium of the former with the tardily 

 differentiated sporophyte of, e.g., Ophioglossum . He is finally led to the 

 suggestion that if the sporogonium of Anthoceros were to develop a root 

 from its basal meristem, it would form thus a sort of " Pro-Ophioglos- 

 sum" from which the known species of Ophioglossum might have de- 

 scended. Through them could readily be derived the other Eusporan- 

 giatae and perhaps all the rest of the Filicales. The first leaf of this 

 primitive Ophioglossum was probably fertile and the sterile leaf blade is 

 believed to have sprung, like 'the root, from the prolific and versatile 

 basal meristem. This well thought-out hypothesis is still far from en- 

 tirely satisfactory. It does however escape at least a part of the force of 

 the criticism recently directed by Scott against the antithetic theory 

 of alternation, that "no one ever saw an intermediate stage between 

 a sporogonium and a leafy stem." It is evident that Campbell needs 

 to postulate the origin of but a single flattened outgrowth from the 

 base of the sporogonium, a structure of the sort which has an actual 

 counterpart in the apophysis of the moss Splachnum. The further evo- 

 lution of the shoot to a "leafy stem" is, if we entertain the rather gener- 

 ally accepted view of the relationship of Ophioglossum to its allies, not a 

 question of hypothesis but of fact.- — D. S. Johnson. 



The Prairies of Iowa. — Although the papers that have been writ- 

 ten in explanation of the prairie are almost numberless, it is with unal- 

 loyed pleasure that we welcome Shimek's recent paper 1 on this subject, 

 since it is one of the first to present exact data. For many years 

 the author has been interested in the study of the tension line between 



1 Shimek, B., The Prairies. Bull. Lab. Nat. Hist. State Univ. Iowa, 6: 169-240, 

 pis. 14. 1911. 



