198 GROWTH AND WORK OF PLANTS 



parts, (a) downward movement of the petal on which the insect 

 lands (in Canna), (b) release of stamens (mountain laurel) or of 

 pollinia in the orchids so that the pollen or pollinium is thrown 

 upon some part of the insects, (c) release of style and stamens 

 which spring and scatters the pollen on the insect (golden chain, 

 Cytisus, etc.). (7) Differences in the length of stamens and 

 styles in different flowers (primrose, Campanula). (8) Mon- 

 oecious or dioecious flowers. (9) Anthers and stigma maturing 

 at different times in the same flower, etc. 



