THE FOXGLOVE 13 



plane which, as usual, passes from the front to the back of the 

 flower. 



The flower is adapted for pollination by humble-bees, the 

 body of which is just of the right size to fill the corolla-tube when 

 they creep into it. They visit the flower for nectar, which is 

 secreted by a greenish-yellow ridge around the base of the ovary, 

 and accumulates in the narrow part of the corolla- tube. When a 

 humble-bee comes to the flower, and its behaviour can be watched 

 on any sunny day by standing for a few minutes beside a Fox- 

 glove, it alights on the lower lip and creeps along the floor of the 

 horizontal or sloping tunnel formed by the corolla-tube. Its 

 back will rub against the upper wall of the tunnel, and the stigma 

 and anthers which lie flat against this (Fig. 3 of Plate). Since 

 the anthers open before the stigma is mature a bee on visiting a 

 flower in an early stage may only receive pollen. On its creeping 

 into another flower, in which the lobes of the stigma have separated, 

 this would be deposited on the inner receptive surface of the 

 stigmatic lobes. When well visited by humble-bees the flowers 

 are usually cross-pollinated, but when visits are few the anthers 

 do not become emptied of their pollen before the stigma has 

 opened. In this case, when cross-pollination is not effected, the 

 flower's own pollen will get on the stigma, when the corolla falls 

 off. Pollination is thus practically certain, and this explains the 

 production of fruit by almost every flower of the inflorescence. 



The fruit of the Foxglove develops from the ovary after the 

 corolla of the flower with the attached stamens has fallen. The 

 calyx remains, and surrounds the young fruit. This becomes a 

 dry capsule with two cavities. When ripe it opens by splitting 

 in the plane of the partition, and the two halves of the wall gape 

 apart, allowing the numerous small seeds developed from the 

 ovules to fall out as the stem sways in the wind. 



HEATHER OR LING (Calluna vulgaris, Salisb.) 



The Common Heather or Ling is widely distributed in Britain. 

 In the north it covers large tracts of moorland as the dominant 

 plant, and it takes a similar place in the bogs of the west of Ireland. 

 Further south it occurs on sandy soil, and in the open parts of the 



