— 394 — 



types as segregation products from tricolor x arvensis. Such 

 segregation products are the following types (Wittrock 1897): 



V. arvensis Murr, ^communis Wittr. var. gotlandica Wittr. (table 



X, fig. 144—152). 

 *curtisepala Wittr. (table XII, fig. 196—203; 



table XIII, fig. 220—224). 

 *sublilacina Wittr. (table XII, fig. 182—195); 

 *sublilacina var. atropurpurascens Wittr. (table 



XIII, fig. 216—218); 

 *striolata Wittr. (table XII, fig. 204—205). 



When Wittrock supposed that he was able to recognize the 

 parental varieties to some other spontaneous hybrids, he mentions, 

 it is quite illusory. 



This investigation shows how little reason there is in the 

 modern splitting up of Linnean species. Had one of these system- 

 atists found my individual from Læsø with the curious e mar gin- 

 ate, nearly laciniate lateral petals, its erect stature and narrow, 

 deeply serrate (fig. 4 b, pag. 369), glaucous and fleshy leaves, 

 I am sure he would have made a new species of it, especially as 

 all the descendents were of the same type. This individual was 

 made the original specimen, and all its characters were inserted 

 in the diagnosis, both the palmate stipules, the long and 

 incurved spur, the acuminate basal petal and the dark spot 

 in front of the style. Now I caused the statistical investigation 

 on the locality to be carried out (table II Z, Æ, 0, pag. 381) and 

 it showed that the character emarginata might be combined with 

 different characters. Of the 16 combinations possible in table II, 

 15 were realized among 100 individuals, this being the total 

 number investigated from these 3 populations. If a new species 

 should be based upon each diverging character such a small locality 

 as Læsø would increase the number of species very much, because 

 the individuals cross, and the new character soon will be combined 

 with a lot of all the earlier known characters. 



Every one, who is engaged in plant-determination, knows 

 the difficulties caused by the fact that most specimens only agree 

 with the diagnosis in some of the characters. In critical plant 

 groups as Viola, where hybrids and stabilized segregation products 

 from crosses are frequent, not only within the species but between 

 the different collective species too, it is in many cases quite im- 



