EXPERIMENTAL EVOLUTION AMONGST PLANTS. 97 



if the}' ^ere found wild and if they held their characters as tena- 

 ciously as they do under cultivation. In fact, the Moss rose was 

 long regarded as a good species, and it was only when its origin 

 began to be understood that this opinion was given up. The 

 earlier botanists, who were less critical about origins than the 

 present botanists are, made species largely upon apparent features 

 of plants, although their fundamental conception of a species was 

 one which was created as we find it, in the beginning. Yet, 

 strangely enough, we at the present day, who profess to regard 

 species as nothing more than loose and conventional aggregations 

 of similar individuals, and which we conceive to have sprung from 

 a common ancestor at some more or less late epoch in the world's 

 history, make our species upon premises which we deny, by 

 giving greater weight to obscurity of origin than we do to similari- 

 ties of individuals. 



The fact is that the practice of systematic or descriptive botany 

 is at variance with the teachings of evolution. Every naturalist 

 now knows that Nature does not set out to make species. She 

 makes a multitude of forms which we, merely for purposes of 

 convenience in classifying our knowledge of them, combine into 

 more or less marked aggregations to which we have given the 

 name species. Very often we find in Nature an aggregation 

 of successive individuals which is so well marked and set off from 

 its associated groups that we consider Nature to have made an 

 out and out distinct species ; but a closer acquaintance with such 

 species shows that, in many cases, the intermediate or outlying 

 forms have been lost and that the type which we now know is the 

 remainder in a continuous problem of subtraction. In other 

 cases, a form appears to have arisen without intermediate forms, as 

 a distinct offshoot from an older type. This is well illustrated in 

 many remarkably distinct garden forms, which originated all at 

 once with characters new to the species or even to the genus. T 

 have mentioned such a case in the Upright tomato. Even the 

 sudden appearance of these strange forms is proof that species 

 may originate at any time and that it can be no part of our funda- 

 mental conception of a species that it shall have originated in 

 some remote epoch. Species-making forever enforces the idea of 

 the distinctness and immutability of organic forms, but study 

 of organisms themselves forever enforces an opposite conception. 

 7 



