i88 FREAKS OF PLANT LIFE. 



Inpiihis), and by a little attention to the habits of this 

 plant we may comprehend the general principle on 

 which all twining plants ascend. The first two or 

 three joints or internodes of the hop, after it emerges 

 from the ground, are straight and stationary. We 

 use the term " internode " as expressing that portion 

 of a stem which lies between one node or knot and 

 the next ; that is, between the point where one leaf, 

 or pair of leaves, spring from the stem, and the like 

 point next above it. After the two or three straight 

 joints, or internodes, of the young shoot of the hop, 

 another one grows, which, whilst still young, is seen 

 not to be motionless, like its predecessors, but to 

 bend on one side and move slowly round, or rotate, 

 like the hands of a watch, with the sun. We have 

 already become familiar with this kind of rotation in 

 plants, but must be prepared to meet with it in 

 twining plants in a more exaggerated degree. The 

 average rate of rotation during the day in hot weather 

 was found by experiment to be two hours and eight 

 minutes for each revolution. When the next inter- 

 node is produced the two continue to rotate, and so 

 on with a third. But as the internodes grow old they 

 cease to revolve. It is the terminal two or three of 

 the internodes that exhibit the movement. A shoot 

 was watched when in full rotation with three inter- 

 nodes. The lowest was a little over 8 inches in 

 length, the second was 3^ inches, and the last, or 



