Ii»(! Viirldtioii ill till- Mdh' Uiip, Huimilus lupulus L. 



Whether any pair of characters (as, for example, the type-characters 

 ennmeratod above) are all('loiii()r])liic pairs is a problem the soliitidii 

 of which has not yet been attempted. 



To the student of genetics the hop-plant is not an ideal subject, 

 because of the comparatively lonji interval^ that must inevitably 

 elapse between the inception of two successive generations, so that it 

 may be many years before any definite results can be obtained. Hop- 

 growing is, however, such an important industry in tliis country that 

 we cannot afford to neglect the application of modern methods in plant- 

 breeding and selection to the hop-plant, in an endeavour to obtain 

 new varieties superior in (|uaiity or in vigour to those already grown, 

 particularly as this j)lant is now receiving the attention of scientific 

 experts both on the continent and in America. 



In conclusion I desire to express my thanks to !\Ir E. S. Salmon, 

 F.L.S., of the Kesearch Department, South-Kastern Agricultural 

 College, whose advice during tiic ])r()gress of tlie work has been most 

 valuable, and also to Mr F. Summers, M.Sc, Botany School, f'andiridge 

 University, who kindly made extracts from works in the library of 

 the University. 



EXPLANATION OF PLATE IV. 



Fio. 1. A tj'pical \onij, lux lateral with its subtending bract. 



Fig. 2. Portion of a liop-bine bearing short, den/ie laterals. 



Fig. 3. Above is shown a rigid, open lateral of an Oregon (J hop; below is the 

 drooping type of lateral of the English forms. 



' At Wye no seedling has been known to flower during its first season, although 

 Dr Johs. Schmidt finds that at Copenhagen his seedlings frequently come into flower 

 the first year {.see Cnrnptes-reiiduf! (lex Immux <lii Liibordloirc tie Cnrlsherg, 1 Ime Vol. 101,5. 

 p. 170); even during the second season the )ilants do not attain to their full vigour and 

 it is evident that certain characters at anv rate arc not constant at that age. 



{Received May 5th, 1915.) 



