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finding them all realized during ones life-time will decrease. It 

 is practically impossible to make a classification of so 

 many systematic units. 



But many of the individuals are heterozygotes, their offspring 

 is inconstant and therefore they have no systematic value, some 

 will say. It is a mere assertion and only supported by custom, 

 that constancy in offspring is the real standard for systematic 

 value. The ecological value of characters as prostrata, atropurpurea 

 and caespitosa is the same, whether they are heterozygotically 

 or homozygotically realized. When the purpose is to classify the 

 individuals, it is more to the point to take a standard that has 

 some relation to the individual itself and not to its offspring. 

 The identical reaction against the conditions is such a standard. 

 All individuals reacting identically against the conditions are of 

 the same ecological value. 



On the other hand, even if we maintain constancy in off- 

 spring as the standard for systematic classification, almost the 

 same number of systematic units are possible as when the reaction 

 is taken as standard; however the units are possibly still more 

 seldom realized. Furthermore my investigations show, that in 

 Viola the homozygotic types are far more frequent in nature 

 than might be expected, so that the difference between the two 

 apprehensions is more of theoretical than of practical significance. 

 In all cases we get a very large number of systematic units within 

 V. arvensis and V. tricolor. 



It is interesting to see how the systematists hitherto have 

 dealt with a polymorphous species like Viola. Wittrock (1896) 

 has given about 40 sub-species, varieties, sub-varieties, forms 

 and sub-forms. The diagnoses comprise nearly all the varying 

 characters, and in most cases the varieties are based upon one 

 or a few individuals. Wittrock's varieties and forms, in most 

 cases correspond with one of my 5,308,416 combinations, and 

 it would be very fortunate if the same combination of all the 

 characters was found once more, that is to say: there is the greatest 

 possibility of finding one of the other 5,308,376 combinations that 

 have no name. Such a division, on the one hand, is quite insufficient, 

 but on the other we cannot reasonably divide all the earth's 

 140,000 "old" species into so many new species, each with a new 

 name. 



Moreover I have been able to recognize several of Wittrock's 



