Books and Current Literature. 177 



contains much that is of great interest, whether it meets the 

 approval of the reader or not. Its more extended review is re- 

 served for the publication of the remaining part. 



In 1903, Mr. George W. Oliver, plant propagator of the 

 Bureau of Plant Industry, undertook a series of experiments in 

 plant breeding which involved the crossing of varieties of lettuce, 

 alfalfa, and cowpea. The bulletin (U. S. Department of Agri- 

 culture, Bureau of Plant Industry, No. 178) which gives in de- 

 tail the methods used and originated in the accomplishment of 

 this was issued in February, 1910, under the title "New Methods 

 in Plant Breeding." 



Both lettuce and alfalfa required special manipulation to 

 prevent self or random cross fertilization. In the former case, 

 Mr. Oliver w^as finally successful in washing the stigma entirely 

 free from pollen without injury by means of a jet of water. He 

 gives a full description of the process and the instruments used. 

 The devices used for lettuce were also useful for other Compositae. 



In alfalfa, the flowers which were selected to furnish pollen 

 were first "tripped" i. e. the stigma was released from the 

 sexual column without releasing the pollen from the anthers 

 by the use of a small pin. The anthers were then removed for 

 future use. The seed-bearing flower was then tripped in the 

 same way and the stigmas kept from pressing against the banner 

 by the pin. After washing with a jet of water it was ready for 

 pollination. 



The size of the cowpea flower made emasculation and de- 

 pollination a much simpler matter. The processes are fully 

 described, and there are chapters upon methods of emasculating 

 and depollinating common flowers, crossing cultivated varieties 

 and natural species, hybridizing species, etc. The paper is well 

 illustrated. 



