186 Yarldtlon !u flif .}f(i/f //oj). II in 



mini?- 



Iu|>ulus 



L. 



of the filands correct to 5/i. One leaf from eacli hill was selertod 

 and measurenieiits taken for those glands showing extreme variation, 

 the smallest glands which appeared to he not fully developed and 

 those w'hich were not more or less circulai' not being taken into 

 consideration. 



The variation was foiuul to Ix' sonunviiat con.sidcral)]^ oven on tlie 

 same leaf; usually it is from 120 /x to 160 /x. No plant was found 

 to have glands consistently large or consistently small, but it was 

 seen that in general those leaves with most numerous glands showed these 

 to be a])ove the average in size. To illustrate this jHiint the following 

 table shows the minimum aiul maximum dimensions of the leaf-glands 

 for those plants already mentioned as possessing numerous glands 

 and those with few : 



That this is not an invariable rule is shown by the fact that occasion- 

 ally where the glands are few in iiumbci tlun- may also reach a size 

 above the average. Two such cas<'s have come under my observation, 

 both plants being hybrid seedling.s raised in the inirsery; one is a 

 monoecious hop (rcf. no. J 2, raised from the (Jerman variety Stirn 

 X cJ Z 12), and the other K 1 to which refereiu'e is made above. Tn 

 each of these the maximum 190 /<, has been reached. 



The petiole. The most interesting feature connected with the 

 petiole is tlie colour; this is never uniform, but (with the exception 

 of those petioles borne by the typical pale green stems) varies on one 

 and the same petiole from green to some shade of red. The lower 

 side is invariably green toward the distal end but may show transitions 

 to red towards its proximal extremity. The colour relation between 

 the petioles and the bines on which they grow is as follows; 



