66 



BRITISH FLOWERING PLANTS 



its breast with pollen from the anthers of flowers when 

 just expanded, and to deposit some on the stigmas of 

 older ones. The flowers are fertilised exclusively by 

 humble bees. The species with short proboscis often 

 pierce the spur, and thus obtain access to the honey, as 

 in Aquilegia. The plant is very poisonous, and is said 

 to have been formerly used to destroy wolves, whence 

 the name Wolfsbane. Any one who has spent a 

 holiday in Switzerland must have noticed in the Alpine 

 meadows that the cattle leave the clumps of Aconite 

 untouched. Darwin ^ quotes from Dr. Ogle a curious 

 illustration of the protection afi'orded by this poison. 

 Ogle examined 100 stems of the white variety, which is 

 harmless, and found that every single flower had been 

 perforated by humble bees. Flowers so treated are 

 robbed of their honey without being fertilised. The 

 blue flowers of neighbouring plants were, however, none 

 of them perforated. They were being visited by bees 

 in the normal manner, and would therefore set their 



seeds. The seeds 

 are jerked out of 

 the follicles by the 

 wind. They are tri- 

 angular, black or 

 deep brown, and 

 much wrinkled. The 

 angles are evidently 

 due to mutual pres- 

 sure. 



The plant is a 

 native of Europe 

 and temperate Asia, 

 and is found wild in Britain only in Wales and a few 

 counties of western England. 



In the yellow-flowered A. Lycoctonum, which, how- 

 ever, is not British (Fig. 37), the petals are even more 

 i-emarkable than in A. Napellus. 



' Cross- mid Self- Fertilisation of Plants, p. 428. 



Fio. 37. — Aconilum Lycoctonum. A, flower in the 

 second (female) condition, fseen from the side. 

 Nat. size. - Ji, longitudinal section, x about 2. 

 The upper stamens have already fallen. 



