180 Varkitio}i in tlic Male Ihip, lluiuulus lupulus L 



Slem {Bine). 



Colour. AIthouf;h the colour of tlie bine varies from a pale green 

 to a (lark red amoiifj the plants under observation, the variation in 

 colour in the individual plant is very slight, in fact, among the English 

 forms of male hops this character appears to be more constant than 

 any other, persisting from year to year in the same hill and in different 

 parts of the garden for hills having the same origin. This is not only 

 true for the pale green and the dark red stems but also for the inter- 

 mediate forms; in the latter the colour is not generally a uniform 

 intermediate shade between green and red, but consists of a mottling of 

 small areas alternately red and green. This mottled appearance is often 

 very marked and may persist to some extent in the green bines and the 

 red bines. In the palest green and darkest reds the mottling is not 

 visible but when these extremes are departed from small red dots in 

 the one case and small green dots in the other appear. In others 

 again the dots are more conspicuous and there is either a green ground- 

 tint with red markings or a red ground with green markings and the 

 general appearance approaches more nearly the intermediate mottled 

 form. 



The coloration of the petiole is associated with that of tiie stem 

 and usually an observation of the petiole of a leaf removed from a plant 

 is sufficient to deternu'ne approximately the colour of the stem from 

 which it was taken. This association of colour will be treated more 

 fully when dealing with the petiole. 



Ri(h/es. The hop-bine is provided normally with six ridges^ corre- 

 sponding in position with the leaf-trace bundles of the vascular cylinder. 

 In colour the ridges are almost invariably darker than the surface of 

 the stem between the ridges. The pale green bines have ridges of a 

 rather less pale green and the red bines have ridges of a darker red 

 except in the very dark ones where the tendency is towards an almost 

 imiform deep red. Occasionally the ridges may be seen to be paler 

 than the general surface, but in such cases transitions to dark ridges 

 will almost certainly be found on the same bine. No case has been 

 observed where the ridges are consistently paler than the rest of the 

 surface and oidy one plant was noticed in which they are nsnnlhj so; 

 this plant, J 3G, is a seedling (raised from the (Jerman variety "Stirn," 

 the male parent being prnhahh/ Z 12) producing a mottled bine with 



' Occasionally a h'mr willi iiiiio ridges and licarinij a wlinrl of llirco leaves at each 

 node is met witli. 



