eo 



In the discussion following this paper a number of interesting facts 

 were brought out relative to the vitality of pollen. The president of the 

 society stated that the pollen of tomatoes would retain its vitality for 

 fully 6 months, as shown by the common practice of gathering pollen 

 during the late summer and fall months from plants grown out of doors, 

 for use in fertilizing tomatoes grown under glass during the winter. 

 According to another statement, grape pollen retains its vitality for fully 

 2 months, and the date palm for a year or more. Carnation pollen may 

 fhe kept in closely stoppered vials for several weeks, and may be shipped 

 from one part of the country to another. In preparing pollen for keeping 

 it should be thoroughly dried and placed in closely stoppered bottles. 

 For plants grown in moist climates the drying should be done in the 

 shade ; for those growing in arid regions, it may be more quickly dried in 

 the sun. It was stated that pollen of certain plants is commonly dis- 

 tributed through the West Indies on dry blotting paper inclosed in paste- 

 board boxes. In this way its vitality is retained for more than 3 weeks. 



A paper giving some suggestions for the classification of Hybrids pre- 

 pared by E. I. Lynch, curator of the Botanic Garden, Cambridge, England 

 showed the desirability of the classification of all results, so that reference 

 can be had to previous work. A plan previously published by the author 

 in tho Journal of the Royal Horticultural Society of London, vol. 25, was 

 briefly outlined. Investigators often want to know what plants have been 

 found to respond in a certain way, or they may desire to reobserve from a 

 new point of view, or carry further results in which they may be interested. 

 This was cited to show the imjDortance of classifying all experimental re- 

 sults, and action of the conference along this line was recommended. The 

 writer requested that he be furnished with accounts of hybrids which at 

 first were nearly barren and afterwarfis became fertile ; also of hybrids 

 which are less fertile than either of their parents. He also asked that 

 suggestions be sent him regarding different systems of classification. In 

 general, he proposes the classification of hybrids based upon their beha- 

 viour, rather than upon the classification of natural orders, genera, or species. 



The Principles of Plant Breeding were difecussed in a paper by Luther 

 Burbank, of Santa Kosa, California, The two influences or forces which 

 control plant and animal breeding are heredity and environment To 

 guide the interaction of these two forces is the sole object of the breeder, 

 whether of plants or of animals. A general knowledge of the relations 

 and affinities of plants is not sufficient for the successful plant breeder, 

 He must be a skillful biologist, and, having a definite plan, must be able 

 to correctly estimate the action of the inherent and external forces which 

 he would control. A plant breeder before attempting to make new 

 combinations should select with great care the individual plants which 

 seem best adapted to his purpose. This requii'es an exceedingly keen 

 perception of minute differences, great patience, and extreme care in 

 treating the organisms operated upon. This applies more particularly to 

 annuals or those plants generally produced by seed. In breeding perennials 

 the first deviations from the original form are often of an almost unap- 

 preciable degree. By careful and intelligent breeding, any peculiarity 

 may be made permanent, and there appears to be no limit to the improv- 

 ment of plants. Cultivation and care may help plants temporarily, but by 

 breeding, plants may be produced which will do better work in all places 

 and for all times. 



W. A. Orton, of this Department, read a paper on the Breeding of 



Disease-Resistant Varieties, in which a resume was given of work being 



.carried on by the Bureau of Plant Industry. The wilt disease of 



