20 VIOLA CUCULLATA. COMMON BLUE VIOLET. 



if attention were turned to watching for variations, and then 

 sowing from those selected, some interesting forms might be 

 obtained. 



The spur of the Violet is worth special investigation by the 

 student. Inside the spur (see illustration on the plate) there is a 

 fleshy, lever-like projection, and it would be a matter of interest 

 to know not only the uses of this projection, but also whether 

 the spur is formed to accommodate it. In this case the spur and 

 staminate projection are proportionate; but some Violets have 

 long spurs and short projections. On the other hand, there are 

 Violets without these projections from the stamens, and then 

 there is no petaloid spur. Some have contended that the pro- 

 jection is used as a lever, which, on being raised by an insect in 

 search of nectar, causes pollen to be thrown on the insect's back, 

 and the pollen is then taken to another flower, thus " cross-fertil- 

 izing" it; but as in this Violet the spur membrane is so closely 

 fitted to the " lever " that it cannot work, it shows how wholly 

 imaginary these speculations are. 



Color is supposed to be a provision of nature to attract insects 



to flowers for this very purpose of " cross-fertilization," But 



the student will not fail to notice that bees at least very rarely 



visit this Violet, though in color it is perhajDS one of the showiest 



of all the subjects of the floral kingdom. Rich ground, if par. 



tially shaded, grows the plant to great j^erfection, and we may 



often see large tracts of such land, in old, abandoned gardens, as 



near a perfect 



" Sea of blue " 



as it is possible to cxjoect from any flower. 



Explanation of the Plate. — i. The plant, sh(3wing its short, thick, and somewhat fleshy 

 rootstock. — 2. A flower divested of petals, showing the heel-like projection which pro- 

 ceeds from two of the stamens and fills the spur of the corolla. — 3. Varieties of color 

 occasionally found. 



