FOXGLOVE, VALISNERIA 



[CHAP. 



contact with the same part of the insect. For instance, 

 in Geranium pratense (Fig. 40), when the flower first 

 opens, the stamens lie on the petals, at right angles 

 with the upright pistils. As, however, they come to 

 maturity they raise themselves (Fig. 41 a), parallel 

 and close to the pistil (Fig. 41 b\ which, however, is 

 not as yet capable of fertilisation. After they have 

 shed their pollen, they return to their original position 

 (Fig. 42), and the stigmas unfurl themselves. More 



FIG. 41. Geranium pratense (young 

 flower). Five of the stamens are 

 erect. 



FIG. 42. Geranium pratense (older 

 flower). The stamens have retired, 

 and the stigmas are expanded. 



or less similar movements have been observed in 

 various other flowers. Thus the cells of the anthers 

 of the Foxglove (Digitalis purpurea) (Figs. 100 102), 

 which are at first transverse, become longitudinal as 

 they ripen. 



In aquatic plants, the blossoms habitually come to 

 the surface. In Valisneria spiralis the female flower 

 has a long spiral stalk which enables it to rise to 

 the top of the water. The male flowers which are 



