60 NYMPH^EA CE&, PAPA VERA CEJE. [CHAP. 



obvious that insects will dust themselves with the 

 pollen and then carry it with them to other flowers. 

 In Berberis, however, both advantages, the dusting 

 and the cross-fertilisation, are promoted by a very 

 curious contrivance. The bases of the stamens are 

 highly irritable, and when an insect touches them the 

 stamens spring forward to the position shown in 

 Fig. 56 and strike the insect. The effect of this is 

 not only to shed the pollen over the insect, but also 

 in some cases to startle it and drive it away, so that it 

 carries the pollen, thus acquired, to another flower. 



NYMPH^EACE^E. 



This order is represented by two British species. 

 Nymphaa alba, the White Waterlily; and Nuphar 

 lutea, the Yellow Waterlily. According to Delpino, 

 N. alba is fertilised by beetles. Sprengel contrasts 

 the large size of the pistil and the great number of 

 the stamens in N. lutea, where the fertilisation is, as it 

 were, a matter of accident, with the small pistil and 

 four stamens of a Labiate ; such, for instance, as the 

 common Dead Nettle, which, as we shall see, are so 

 beautifully arranged with reference to one another, and 

 where consequently so much less pollen is required. 



PAPAVERACE^E. 



Of this family the Common Poppy is the best 

 known representative, though the Celandine is also 

 common on roadsides, especially near villages. The 

 Poppy has two sepals, which drop off as the flower 

 expands ; four petals ; numerous stamens, forming 



