CURRENT LIHERATORE. 
BOOK REVIEWS. 
The culture of plant rusts. 
THE ALTERNATION of wholly unlike forms in many Uredineae, the 
aecidium on the one hand, and the uredo- and teleutospores on the other, and 
especially the occurrence of these forms upon unrelated hosts in the heter- 
cecismal species, has given to the study of the rusts by the culture method a 
most absorbing interest. No law has been detected governing the selection 
of alternate hosts by the different species of rusts, and so each new instance 
brought to light is an independent discovery, worked out with little or no aid 
from previous records. As the work progresses, the number of possible com- 
binations between known forms necessarily diminishes, but new forms are 
found, and known forms are divided up by previously undetected characters 
The study of rusts by cultures began in 1865, and has been especially 
active during the last decade. The results have opened up many intricate 
problems, none of which has been more discussed and seemed more weighty 
than that of the relationship of what have been called physiological species 
orraces, The literature of the subject has become abundant and widely 
scattered, until even a specialist finds it difficult to follow. 
The need of a work in which the results thus far attained by culture 
methods are collected, arranged, and summarized is a real need, and one 
which has been happily met by Dr. H. Klebahn,’ of Hamburg, in a treatise 
on the heteroecismal rust-fungi. 
Although it has taken nearly 450 large octavo pages in which to present 
the subject, the work could not be surpassed for concise and lucid treat- 
ment, and for completeness without redundancy. It is an admirable account 
of the subject. 
The author begins his treatise with a short account of other organisms, 
both animal and plant, that possess heteroecismal adaptations, and then takes 
up the history of the knowledge of the heteroecismal rusts. In the pages 
that follow the natural distribution of the aecidiospores, uredospores, and 
sporidia are discussed, and the methods of natural infection. All available 
information is presented regarding such questions as: Can the uredo and 
teleutosporic generation of heteroecismal rusts arise from sporidia, and can 
aecidia of heteroecismal rusts arise in any other way than from sporidia? 
These are the questions of much economic interest. 
*KLEBAHN, H., Die wirtswechselnden Rostpilze. 8vo. pp. xxxvii-+ 447. Berlin: 
Gebriider Borntraeger. 1904. Jf 20. 
1904] 223 
