38 FIELD AND WOODLAND PLANTS 



In other climbers the blade of the leaf is not reduced in size, 

 even though the leaf serves the purpose of a tendril, the function of 

 clinging being assigned exclusively to the petiole or leaf-stalk. This 

 may he observed in the Wild Clematis and the Bryony, in both 

 of which the petiole forms a ring round any branch or stem with 

 which it comes in contact. These petioles are apparently equally 

 sensitive on all sides, and are therefore ready to cling to any available 

 support, whether above or below. In the Clematis the leaves are 

 at first at right angles to the stem of the plant, but they after- 

 wards turn downwards, and thus transform themselves into so many 

 anchors which give additional aid in supjoorting the climber among 

 the other hedgerow plants and shrubs. 



