Repeated Mutations Due to the Same Causes. 465 



taken away from, their type. I have often hacl /a/a-plants 

 from two or three sources, e. g., the 1st, 2d and 5th gen- 

 erations, growing side by side in my garden; they were 

 quite indistinguishable from one another. 



Intermediate forms seem to be associated more with 

 some mutations than with others. Rarest with O. nanella, 

 they are commonest with 0. laevifolia. Sometimes the 

 intermediate forms repeat the new type of their species 

 more or less completely in the lateral branches which 

 arise from the axils of the rosette leaves (as for example 

 an O. laevifolia which exhibited excessive crumpling on 

 the leaves borne on the main stem). In this case they 

 may be regarded as individuals in which the typical char- 

 acter of the species is more or less latent at first. 



Thus these apparent transitional forms are not the 

 steps by means of which the new species has attained its 

 full development. They are rather the imperfect copies 

 of a perfect picture which already exists. They are, in 

 a word, the extreme variants of the perfectly constant 

 new type (see §§24 and 25). 



It is in this very respect that the newly formed spe- 

 cies behave in a diametrically opposite way to the races 

 built up by the accumulation of fluctuating characters 

 (Part I, § 7, p. 71) ; and it is this fact which justifies 

 their title to specific rank. 



The general conclusion of this argument is : 



At the beginning of my observations, in the year i886, 

 the characters of the nezv species, zvhich appeared later 

 in my cultures, were already present in the plants in the 

 field at Hilversum in a latent condition. They remained 

 in that condition for many generations, both there and in 

 my cultures, and only appeared from time to time, espe- 

 cially in large sowings. 



