E. S. Salmon 199 



flowers gave 15 hops with 261 seeds, and the "control" branches 58 hops 

 with no seeds. 120 normal seedlings were raised, nil climbers and 

 fertile^ — no "dwarf" appearing among them. 



In a fourth cross (Ref no. 14/09) the English female variety Canter- 

 bury Whitebine was pollinated from a male hop obtained from Oregon, 

 U.S.A., which possesses vegetative characters distinct from all the 

 English forms of H. Lupulus. 110 hops, containing 899 seeds, were 

 obtained from the pollinated flowers, and 85 hops, containing 2 seeds, 

 from the " control " branches. 109 seedlings were raised, of which 79 

 were climbers and fertile, and 30 " dwarfs " and sterile. In this " cross," 

 however, many of the " dwarfs " were extremely stunted, and were weakly 

 from the first, and died in the first or second year after germination 

 before a count was made. It is certain, therefore, that the proportion 

 of " dwarfs " to climbers in this " cross " is considerably higher than 

 30 to 79, which are the numbers of plants surviving in the fourth year 

 after germination. 



The only apparent reference to " dwarfness " in H. Lupulus which I 

 have been able to find is in a Bulletin^ by Dr W. W. Stockberger and 

 J. Thompson, where a bare mention is made of the occurrence of " hills 

 with dwarfed vines" in a Californian hop-field. 



Figdor {I.e.) has recorded the occurrence among seedlings of the 

 annual species Humxdus japomcus of some individuals which showed 

 a dwarfed habit. //. japonicus usually attains a height from the 

 ground of 1*5 to 2m.; the tallest of the "dwarf" seedlings measured 

 only 0*41 m. and the shortest 0*11 m. 



Upon such dwarf plants which seemed to be otherwise males were 

 developed flowers hermaphrodite in various degi-ees (for details see 

 original paper), and in a few cases female flowers also were formed. 

 Figdor sought to explain the production of these dwarfs as follows : " Der 

 Nanismus der einzelnen Individuen wird durch die gleichzeitige Ein- 

 wirkung einer bestimmten chemischen Lichtintensitat bei verhaltnis- 

 massig niedriger Temperatur und ebensolchem Feuchtigkeitsgehalte 

 der Atmosphare in Verbindung mit Nahrungsmangel hervorgerufen." 



The "dwarfs" of H. Lupulus described above differ in being 

 absolutely sterile, and whatever may be the true explanation of the 

 appearance of " dwarfs " in H. japonic^, it is certain that " dwarfness " 

 in H. Lupulus cannot be attributed to the influence of outside factors, 



^ 108 were ? , 11 were s , and 1 was monoecious. 



■^ Some Conditions influencing the Yield of Hops (U.S. Department of Agriculture, 

 Bureau of Plant Industry, Circular No. 56 (1910)). 



