HI.] VIOLACE&. 65 



not secrete honey. The stamens are numerous. As 

 the pistil projects above them, insects, in alighting on 

 the flower, generally touch the pistil before the 

 stamens ; and cross-fertilisation must therefore often 

 take place. At the same time, if from any cause 

 insect-visits are deferred, the flower is almost sure to 

 fertilise itself. 



VIOLACE^E. 



This order is limited in Europe to the single genus 

 Viola, of which we have, according to Bentham, five 

 English species. Besides the showy, coloured flowers 

 with which we are all familiar, most of the species 

 possess minute flowers, which, however, produce abun- 

 dance of seed. These appear later in the year, 

 and are not only much smaller than the others, 

 but almost without petals. In fact, according to Ben- 

 tham, the Pansy ( V. tricolor) is the only one of our 

 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 much less expenditure of material, the 

 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 



F 



