ORIGIN OF A LAN'l) FLORA 215 



of plants are prevented from advancing into each other's do- 

 main bv reason of two entirely different causes, the inability 

 of the one group to cope with unfavorable physical coiidi- 

 tions, and the equally pronounced incapacity of the other to 

 meet and overcome an adverse living environment. 



TJic Orh^iii of (I Land Flora, by Professor F. O. Bower, 

 published by MacMillan and Company. 



Prof. Bower's work on the Origin of a Land Flora, 

 which is an elaborate presentation of the strobilar hypoth-.'sis, 

 will find a cordial welcome at the hands of all botanists and 

 biologists. Perhaps no more important, certainly no r'Ore 

 interesting work has appeared on the subject of plant rela- 

 tionships. Whatever preconceived ideas the reader may 

 ha\e regarding the strobilar hypothesis when he picks up the 

 book he is very likely to become its devoted adherent be tore 

 he lavs it down. The book is so large, it numbers 727 pages, 

 and so important that it merits a critical review, but as it 

 also is many-sided it occurs to the writer that one phnse, 

 namely, the value to the teacher of plant morphology, may 

 well be touched on in this place with no pretense of present- 

 ing an adequate review. In brief, the value to the teacher 

 of the strobilar theory, as given by Bower, will lie very 

 largely in the unlhcation which it will bring, — it w^ill be found 

 to be the red thread which will bind together apparently 

 isolated facts and make them logical, more easily presented 

 and more readily comprehended. 



The first portion of the work treats specifically of the 

 origin of the sporophyte as being especially adapted to the 

 terrestrial habit. Plants with the alternating phases strongly 

 marked, the Archegoniat;e, are amphibious, those with sporo- 

 phvte the predominating phase are wholly land forms, !)ut 

 manv still carry e\'idences of an earlier water habit in certain 

 gametophytic peculiarities, plants in which the sporophvte, 

 the asexual generation, has not appeared, are wholly aqu;;Mc. 



