176 GROWTH AND WORK OF PLANTS 



the brush on the outside of the closed stigma sweeps out the 

 pollen. The stigma now opens, the lobes curving outward so 



Fig. 134- 



Proterandry in the bellflower (Campanula). Left figure shows the syngenoecious stamens 

 surrounding the immature style and stigma. Middle figure shows the immature stigma being 

 pushed through the tube and brushing out the pollen; while in the right-hand figure, after 

 the pollen has disappeared, the lobes of the stigma open out to receive pollen from another 

 flower. 



that the pollen does not fall on its upper receptive surface, but the 

 visiting insect brings pollen from another flower. 



294:. Flowers in which the pistils mature first. In the 

 figwort the flower is urn-like, and the mature stigma is thrust out- 

 side of the flower by the long style, while the stamens are curved 

 backward in the flower. When the stigma of this flower is past 

 the receptive stage, the stamens straighten out and bring the 

 anthers to the outside of the flower, where they shed their pollen 

 so that a visiting insect can carry it to another flower in which 

 the stigma is receptive. In the skunk cabbage the stamens in 

 the flowers of some plants mature first, while in other plants the 

 pistils mature first. 



295. Movements executed by stamens or pistils to aid in 

 cross-pollination. The movements of the pistils and stamens 

 described in the study of the sunflower (paragraph 258) and of 

 the bellflower in the preceding paragraphs are illustrations. A 

 remarkable case is seen in the mountain laurel (Kalmia). The 

 stamens are bent outward and the anthers are held in little pockets 



