Fruits and Seeds. 1 79 



rest of the plant, and open by the three equal 

 valves (fig. 66), resembling an inverted tripod. 

 Each valve contains a row of three, four, or five 

 brown, smooth, pear-shaped seeds, slightly flattened 

 at the upper, wider end. Now the two walls of 

 each valve, as they become drier, contract, and so 

 approach one another, thus tending to squeeze out 

 the seeds. These resist some time ; but at length 



Fig. 67. DOG VIOLET. Seed-vessel after ejecting the seeds. 



the attachment of the seed to its base gives way, 

 and it is ejected several feet, this being no doubt 

 much facilitated by its form and smoothness. I 

 have known even a gathered specimen throw a 

 seed nearly 10 feet. Fig. 67 represents a capsule 

 after the seeds have been ejected. 



6. Now we naturally ask ourselves what is the 

 reason for this difference between the species of 

 violets ; why does the Sweet Violet conceal its cap- 



N 2 



