Elementary Species in Nature 41 



and thousands of minor races, which would 

 show their peculiar characteristics if tested by- 

 cultures in adjacent beds. This however, is not 

 what happens. As a matter of fact V. tricolor 

 and F. arvensis are widely distributed but 

 wholly constant types. 



Besides these, there occur distinct types in 

 numerous localities. Some of them evidently 

 have had time and opportunity to spread more 

 or less widely and now occupy larger regions or 

 even whole countries. Others are narrowly lim- 

 ited, being restricted to a single locality. Witt- 

 rock collected seeds or plants from as many 

 localities as possible in different parts of 

 Sweden and neighboring states and sowed them 

 in his garden near Stockholm. He secured 

 seeds from his plants, and grew from them a 

 second, and in many cases a third generation in 

 order to estimate the amount of variability. As 

 a rule the forms introduced into his garden 

 proved constant, notwithstanding the new and 

 abnormal conditions under which they were 

 propagated. 



First of all we may mention three perennial 

 forms called by him Viola tricolor ammotropha, 

 V. tricolor coniophila and V. stenochila. The 

 typical V. tricolor is an annual plant, sowing 

 itself in summer and germinating soon after- 

 wards. The young plants thrive throughout 



