E. S. Salmon and H. Wormald 



265 



of susceptibility to mildew. Again, a large number of " cuttings " have 

 been taken from a large number of seedlings some of which were immune 

 from, and the rest susceptible to, mildew in the greenhouse ; the dis- 

 tinctive characters of each seedling remained constant'. 



A certain range of variation is found in each series of characters, the 

 extreme forms in some series being widely different, as in the green-bine 

 and the red-bine forms, and in the resistant and the very susceptible (to 

 mildew) forms. There is no evidence of correlation of any one character 

 with the others, with the possible exception of the case of the three very 

 early ^ plants in which very early flowering is associated with a green 

 bine and many leaf-glands. The cases of apparent correlation (to which 

 reference has been made on p. 256) between (1) the number of glands on 

 the leaves and the " condition " of the hop-cone, and (2) between the 

 colour of the bine and petiole and the colour of the strig, cannot perhaps 

 be considered as the association of distinct characters but rather as mani- 

 festations- of the one character (glandulation in the one case — production 

 of a red colouring matter in the other) in different organs. 



A classification to include all forms is at present impossible as the 

 evidence at hand suggests that given an unlimited number of seedlings 

 a gradual transition would be found between the extreme types of each 

 series and even an approximate estimate of the possible number of com- 

 binations of characters cannot be given. 



The accompanying table however may prove of interest as indicating 

 the combinations of character with respect to time of flowering, colour 

 of bine and the relative number of glands on the leaves as shown by the 



Green 



Colour of the Bines 



Mottled green and red 



Red 



/ Early $ 



(* very early) $ 



Time I ,,. n 



f j Midseason ^ 



Flowering " + 



Late $ 



^ „ ? 



3 

 1 



17 

 22 



4 

 11 



5 

 4 



46 

 62 



3 

 50 



6 

 1 



49 

 42 



1 



28 



Many Moderate Few Many Moderate Few Many Moderate Few 

 number number number 



Relative number of Glands on the Leaves 



1 No "cross "-breeding of the different forms has yet been carried out. Seeds collected 

 from " open " flowers of a $ seedling (Z 25) immune to mildew produced 33 seedlings, 

 which when tested for mildew-susceptibility in the greenhouse, proved to consist of 

 24 immune and 9 susceptible plants (7). 



