Books and Current Literature. 99 



changed under the so-called American rules, have been retained. 

 It is the opinion of the reviewer that if they had been followed 

 more closely and more consistently the book would have gained 

 in value and popularity. The retention of the naine Compositae 

 for the whole Sunflower farnily, including the Cichorieae and the 

 Ambrosieae, will meet with almost universal approval. 



The region covered by this work is that of the central 

 Rocky Mountains. It aims to describe all of the species occurring 

 in Colorado, Wyoming, Yellowstone Park, and the Black Hills 

 of South Dakota, and covers also the most of Montana, southern 

 Idaho, the eastern half of Utah, and the northern half of New 

 Mexico and adjacent Arizona. All botanists throughout the 

 Pacific states will find it helpful in their work. 



The descriptions are carefully drawn, care being used to in- 

 clude the essential characters without useless waste of space. 

 The general distribution of each species and variety is given but 

 specific localities are not mentioned. One of the most pleasing 

 features of this flora consists in the compact and intelligible 

 keys, not only to the families and genera but to the species as 

 well. They are dichotomous in the main and may be easily 

 followed, even by the beginner. Professor Nelson is to be con- 

 gratulated on having given us a very valuable and useful treatise 

 on the botany of this interesting region. 



University of California. 



BOOKS AND CURRENT LITERATURE. 



Among the more important data and conclusions of a recent 

 paper by Leroy H. Harvey on The Floristic Composition of the 

 Vascular Flora of Mt. Ktaadn, ]\Iaine (IMich. Acad. Sci. 1909), 

 are the following: The arctic-alpine element of Mt. Ktaadn 

 includes 1 18 species which constitute 54 per cent of the total flora 

 of the mountain. Of these 1 IS species, 67 occur in Arctic Europe 

 and 42 in Arctic Asia; but of the 67 Ktaadn species in common 

 with Arctic Europe only 24, or 35 per cent are known in Arctic 

 Asia, while of the 42 Ktaadn Asiatic forms 34, or 80 per cent, 

 are common with Arctic Europe. 



From these and other data previously set forth by Hooker 

 and others^ it appears that Arctic Europe is the main center of 

 glacial distribution, and that from this two prominent routes, 



