28 The Ottawa Naturalist. [May 



deserts, to have a heavy coat of gray or white woolly hairs. 

 In some eases it has been actually proven that the production 

 of the woolly hairs is directly induced by the hot climate and 

 that plants covered with dense hairs will drop these if trans- 

 planted into a climate of greater humid it v. 



The important influence upon the general configuration 

 of plants exercised by the environmental conditions leads 

 naturally to the practical question: "Is is possible to produce, 

 by changing the climatic conditions, new types or new plant 

 species?" If a species is defined as a unit, provided with certain 

 constant characters, we must answer that, as far as our ex- 

 perience shows, it is not possible to produce new plant species 

 by changing the outer conditions; no facts exist to support the 

 opinion of Lamarck as to the hereditary quality of acquired 

 characters in plants. 



The aforesaid variations are all prodticed by the influence 

 of different external factors upon individuals. When speaking 

 of "variations'' in ordinary parlance, however, we usuallv think 

 of something quite different. We speak of the great variation in 

 roses and apples, by which we mean that there occur a great 

 number of types in apples and roses. The forms which generally 

 are termed individual variations do not refer to the changing of 

 a certain type or a certain individual, but simply to the existence 

 of types possessing different characters. When speaking of 

 "variation" people have been inclined to associate with the 

 term the idea that something is changing. When speaking of 

 individual A T ariation within a species they ordinarily assume 

 that a given individual can become permanently altered in 

 character in one direction or another, that, in fact, a certain 

 main type can produce a number of different, constant varieties. 

 Such a conception, however, leads to confusion and to a mis- 

 interpretation of the phenomena connected with the species 

 idea and the proper idea of variation. 



When we speak of the apple species, for instance, we must 

 remember that the word species is only an abstract which 

 use for all kinds of apples. And when we say that this species 

 or that species is very variable, we simply mean that it consists 

 of a number of distinct types. 



The practical importance of "individual variation" in a 

 plant species is now clear. It simply means that nature herself 

 has provided for a great number of concrete types which, from 

 a practical point of view, are of very different value. And, 

 when we say that we use the individual variation of a species 

 for practical purpose, we really mean that we use the life-types 

 or bio-types of the species in question. 



