162 PLANTS OF THE ALPINE MEADOWS 



the groove immediately above the entrance to the 

 flower. Thus the plant visited is cross-fertilised. 

 As the insect pushes its proboscis between the ring 

 of stamens and the style, its head becomes dusted 

 with pollen, exuded from the inner side of the anthers, 

 and this pollen is carried away to another plant. All 

 risk of transferring the pollen of one flower to the 

 stigma of the same flower, as the insect withdraws its 

 head, is prevented by the little triangular flap above 

 mentioned, which is automatically forced upwards by 

 the insect's head and thus shields the stigma. 



In addition to the larger and more showy flowers 

 of the Field Pansy, adapted to cross-pollination, other 

 much smaller and less conspicuous flowers may be 

 found to occur, which are self-pollinated. In other 

 species of Violet, such as the Sweet Violet (Viola 

 odorata, Linn.), which is not Alpine, some of the 

 flowers are not only self-pollinated, but never open, 

 and after fertilisation, bury themselves (i.e., the whole 

 flower) in the soil. 



The fruits of the Field Pansy are also very interest- 

 ing. The ovary bears many small seeds in a single 

 chamber. When ripe, the fruit becomes erect, though 

 formerly pendulent, and in dry weather the ovary 

 splits into three valves, each of which has usually 

 three rows of seeds. The valves dry up and contract, 

 and thus the seeds are pressed firmly against one 

 another, and are shot out one by one, often to a con- 

 siderable distance. A space of 3 feet has been 

 recorded. We can imitate this mechanism for seed 



