38 THE PLANT WOELD 



We liave received many words of commendation from our sub- 

 scribers on the fine appearance of our January issue, and we liave been 

 pai-ticularly gratified Avitli the cordial support extended to the journal 

 by former readers of the Asa Gray Bulletin. In this connection we 

 would call the attention of our readers to the demand for back volumes 

 of the Bulletin, which will shortly result in exhausting the stock. We 

 can still supply a limited number of complete sets at a price which is 

 quite low in view of the fact that the Bulletin is now extinct, and will 

 increase in value and interest for that very reason. 



The two beautiful half-tones accompanying this issue of the Sup- 

 plement were made from photographs taken by Mr. Carl Krebs, of 

 Cleveland, Ohio. They are the first of a large series of similar photo- 

 graphs of plant subjects recently purchased by The Plant World from 

 Mr, Krebs, which will appear from time to time in our pages. We 

 have acquired the exclusive rights of publication for these photographs, 

 although prints may be secured from Mr. Krebs. 



BOOK REVIEWS. 



Contributions from the U. S. National Herbarium, Vol. VII. No. 1. 

 A Monograph of the North American Umbelliferae, by John M. 

 Coulter and J. N. Rose. Issued December 31, 1900. Government 

 Printing Ofiice. 



A copy of this valuable contribution reached us on the last day of 

 the year, in time to signalize by its production the closing quarter of a 

 memorable century of botanical activity along taxonomic lines. Not 

 the least remarkable feature of this period has been the development of 

 the modern theory of a monograph. In the earlier years of the cen- 

 tury, notably in the works of LeConte and Torrey, we are accustomed 

 to find a bare conspectus of the known species of a genus, ^nth brief 

 descriptions, and possibly a short key. This rather unsatisfactory 

 style of treatment has been succeeded by more and more elaborate 

 works, until at the present time a monograph frequently contains, in 

 addition to a full exposition of sjaionomy, an enumeration of all the 

 herbarium specimens consulted, and a discussion of the systematic 



