in.] 



VIOLA. 



59 



English species in which the showy flowers generally 

 produce seed. The presence of these two totally 

 different kinds of flowers is a very interesting fact ; 

 and as the smaller, or as they are called, " cleisto- 

 gamous" flowers are sufficient to reproduce the 

 species, and of course have the advantage of 

 requiring a much less expenditure of material, the 



Fio. 57 Fig. 58. 



Fig. 57 Section of a flower of Viota caninn. 



Fig. 58. — Stamen of ditto. 



persistence of the showy ones can only, I think, be 

 accounted for by the fact that the ordinary flowers 

 are useful in securing an occasional cross, as the 

 cleistogamous flowers habitually fertilise themselves. 



Viola canina. The structure of the coloured flowers 

 is very curious, and has been well described by 

 Sprengel. The petals are five in number, and irregular 

 in form ; the median one being produced into a 



