114: PROPAGATION OF PLANTS. 



concretely, the species is the sum of such individuals." 

 But as we know little or nothing of the "type or 

 original" of what we now call a species, it is very diffi- 

 cult and often impossible to distinguish theni from 

 varieties ; or, in other words, where there are various 

 closely allied normal or wild varieties, each extending 

 over extensive areas of country, or even when they are 

 more or less intermingled, it is scarcely possible to deter- 

 mine which is the original type or species. Dr. W. B. 

 Carpenter, in referring to this subject and the tendency 

 of some species to run into spontaneous variations, for 

 which no external cause will account, very truly says : 

 " Hence, in discriminating what are real species from 

 what are simple varieties, the botanist is treading on very 

 insecure ground, until he has ascertained, for every 

 species, its tendency to run into varieties of form, 

 whether spontaneous or induced by change of external 

 conditions. His greatest difficulty arises from those 

 cases in which have arisen what are termed permanent 

 varieties, which reproduce themselves with the same 

 regularity as do real species." It may be said on this 

 subject that the most thorough and experienced investi- 

 gators are the least positive in determining what should 

 or should not be called a species, while the superficial 

 writers and observers are usually quite ready at all times 

 to decide such questions to their own satisfaction, if not 

 to 'that of any one else. 



If a plant in its wild or cultivated state reproduces 

 itself from seed with slight or no variation, this fact 

 would not prove it to be a distinct species, but merely 

 show that the natural forces of the plant were very nearly 

 or perfectly balanced. It may be said, in a general way, 

 that species differ from varieties by possessing characters 

 that through a longer period of interbreeding have be- 

 came more firmlv established under uniform conditions. 



Plants in a state of nature perpetuate their species and 



