228 



THE STUDY OF FLOWERS. 



conspicuous, because in close set inflorescences (Umbelli- 

 ferae) ; flowers clustered in " heads " (Clover and Com- 

 positae); with conspicuous sterile flowers surrounding 

 " head " (Cornflower) ; and so on. By this means pupils 

 may be encouraged to observe more closely the intimate 

 relations between insects and flowers. 



The secretion of nectar and in some cases excess of 

 pollen, together with the production of scent and the dis- 

 play of coloured petals, etc., are facts which may be grouped 

 together as arrangements inviting insects to the flowers. 



5 POST. PETAL 



(STANDARD) 



.-_. LATERAL PETAL 

 (ALA) 



-ANT. PETALS 

 (KEEU 



STIGMA 



STAMINAL TUBE 



, POST. SEPAL 

 POST. STAMEN 



OVARY 



Fig. 95. Section of the Pea Flower. 

 The staminal tube is formed by the lower parts of the united stamens. 



In many cases these arrangements are backed up by further 

 devices ensuring that the visiting insects shall render some 

 unconscious service in return. The simpler instances of 

 this kind should be examined as opportunity offers. 

 Examples are here indicated. 



The most familiar is undoubtedly that of the Pea family 

 (Leguminosae), all the British examples of which have 

 papilionaceous flowers. Examples are Broom, G-arden Pea, 

 Rest Harrow, Vetches, etc. Flowers of this type should be 



