THE CANTERBURY BELL FAMILY 401 



torsion, and the tendril can be pulled straight without any 

 twists being left in it. If, on the other hand, a continuous 

 spiral is strained, the convolutions can be effaced, but kinks 

 are left in it, and a break is likely to ensue at any one of 

 them. In a strong wind, therefore, the continuous spiral 

 would be broken, whilst the plant with tendrils in reversed 

 spirals " rides out the gale with a long range of cable paid 

 out." The coiling of the tendrils brings the plant and its 

 support close together in calm weather, and enables them to 

 separate somewhat in a storm. The reversed spiral is not 

 uncommon in nature. It is frequent in the twining stems of 

 MiUilenheckia. It is often found where a long band, whose 

 ends are fixed, has to be packed in a short space, e.g., the 

 intestines of the tadpole, the pond mussel, and the colon of a 

 ruminant. It may be well seen in the tendrils of Sicyos 

 australis. 



From this short account, it may be gathered that the 

 tendril is one of the most perfect of Nature's contrivances. 

 Those who wish to pursue their investigations further, should 

 read Darwin's classic work on Climbing Plants. 



Campanulaceae. 



(Including Lobeliaceae.) 



The Canterbury Bell Family. 



Pollination.— The flowers of this family approach in typo those of the 

 Composites. The anthers ripen first, and the style receives pollen shed by the 

 anthers, while the stigmas are closed. The flower afterwards becomes female, 

 and, if not insect-pollinated, self-pollination takes place in a similar way to that 

 described under Compositae. (For further details, see Wahlenbergia) . 



